--- title: Understanding Why a Text Message to a Lead Shows as Undelivered description: Understand why SMS messages may be marked “Undelivered” in Sierra Interactive, what error codes mean, and how to reduce filtering. image: https://www.sierrainteractive.com/wp-content/uploads/2022/07/Website-Preview-V2A.jpg --- [Skip to content](https://help.sierrainteractive.com/helpcenter/understanding-why-a-text-message-to-a-lead-shows-as-undelivered#main-content) [Contact Support](https://help.sierrainteractive.com/helpcenter/kb-tickets/new?hsLang=en) [![Sierra Interactive logo](https://help.sierrainteractive.com/hs-fs/hubfs/sierra%20interactive%20logo.png?width=250&height=34&name=sierra%20interactive%20logo.png)](https://help.sierrainteractive.com/helpcenter?hsLang=en) - [Sierra CRM Login](https://client.sierrainteractivedev.com/login.aspx?sn=sierrainteractive.com) - [Sierra Support](https://share.hsforms.com/1-PkIvKPkRJ2Oe4iP28LPugcrxj0?__hstc=240356316.ca34a03f98730f420ad639300528f2a2.1764955183725.1783970890126.1783975123568.351&__hssc=240356316.31.1783975123568&__hsfp=3cbed2008eb4c720102b6f72b9dd6767) - [Training & Learning](https://info.sierrainteractive.com/live-training-learning-opportunities) Show submenu for Training & Learning - [Sierra Academy](https://info.sierrainteractive.com/sierra-academy) - [Live Training Sessions](https://help.sierrainteractive.com/helpcenter/join-live-training-sessions-explore-sierra-learning-resources) Show submenu for Live Training Sessions - [Tuesdays 11AM ET](https://us02web.zoom.us/j/81520282538) - [Wednesdays 1:30PM ET](https://us02web.zoom.us/j/84246589732) - [Fridays 3PM ET](https://us02web.zoom.us/j/86964951435) - [Sierra YouTube Channel](https://www.youtube.com/@sierrainteractive/featured) - [Sierra Facebook Mastermind](https://www.facebook.com/groups/sierrainteractive) - [Referral Dashboard](https://www.sierrainteractive.com/customer-referral-dashboard/) - [Operations & Closures](https://info.sierrainteractive.com/sierra-interactive-observed-holidays) - [System Status](https://status.sierrainteractive.com/) Open main navigation Close main navigation - [Sierra CRM Login](https://client.sierrainteractivedev.com/login.aspx?sn=sierrainteractive.com) - [Sierra Support](https://share.hsforms.com/1-PkIvKPkRJ2Oe4iP28LPugcrxj0?__hstc=240356316.ca34a03f98730f420ad639300528f2a2.1764955183725.1783970890126.1783975123568.351&__hssc=240356316.31.1783975123568&__hsfp=3cbed2008eb4c720102b6f72b9dd6767) - [Training & Learning](https://info.sierrainteractive.com/live-training-learning-opportunities) Show submenu for Training & Learning - [Sierra Academy](https://info.sierrainteractive.com/sierra-academy) - [Live Training Sessions](https://help.sierrainteractive.com/helpcenter/join-live-training-sessions-explore-sierra-learning-resources) Show submenu for Live Training Sessions - [Tuesdays 11AM ET](https://us02web.zoom.us/j/81520282538) - [Wednesdays 1:30PM ET](https://us02web.zoom.us/j/84246589732) - [Fridays 3PM ET](https://us02web.zoom.us/j/86964951435) - [Sierra YouTube Channel](https://www.youtube.com/@sierrainteractive/featured) - [Sierra Facebook Mastermind](https://www.facebook.com/groups/sierrainteractive) - [Referral Dashboard](https://www.sierrainteractive.com/customer-referral-dashboard/) - [Operations & Closures](https://info.sierrainteractive.com/sierra-interactive-observed-holidays) - [System Status](https://status.sierrainteractive.com/) - [Contact Support](https://help.sierrainteractive.com/helpcenter/kb-tickets/new) Search Help Center - There are no suggestions because the search field is empty. 1. [Help Center](https://help.sierrainteractive.com/helpcenter?hsLang=en) 2. [Lead Management](https://help.sierrainteractive.com/helpcenter/lead-management?hsLang=en) 3. [Calling & Dialer Tools](https://help.sierrainteractive.com/helpcenter/lead-management?hsLang=en#calling-dialer-tools) September 3, 2026 # Understanding Why a Text Message to a Lead Shows as Undelivered ## Learn why some texts are marked “Undelivered,” what causes it, and how to reduce filtered messages. ### Table of Contents 1. [Understanding SMS Deliverability](https://help.sierrainteractive.com/helpcenter/understanding-why-a-text-message-to-a-lead-shows-as-undelivered#understanding) 1. [When a Message Is Marked “Undelivered”](https://help.sierrainteractive.com/helpcenter/understanding-why-a-text-message-to-a-lead-shows-as-undelivered#undelivered) 2. [What the Twilio Error Codes Mean](https://help.sierrainteractive.com/helpcenter/understanding-why-a-text-message-to-a-lead-shows-as-undelivered#error) 3. [Carrier Filtering Context](https://help.sierrainteractive.com/helpcenter/understanding-why-a-text-message-to-a-lead-shows-as-undelivered#filtering) 4. [Twilio Insights](https://help.sierrainteractive.com/helpcenter/understanding-why-a-text-message-to-a-lead-shows-as-undelivered#insights) 5. [What Sierra Has Implemented](https://help.sierrainteractive.com/helpcenter/understanding-why-a-text-message-to-a-lead-shows-as-undelivered#implemented) 2. [Best Practices](https://help.sierrainteractive.com/helpcenter/understanding-why-a-text-message-to-a-lead-shows-as-undelivered#best-practices) 3. [Troubleshooting Common Issues](https://help.sierrainteractive.com/helpcenter/understanding-why-a-text-message-to-a-lead-shows-as-undelivered#troubleshooting) 4. [FAQs](https://help.sierrainteractive.com/helpcenter/understanding-why-a-text-message-to-a-lead-shows-as-undelivered#faqs) --- ### Why This Feature Matters Text deliverability issues can impact your ability to connect with leads—especially if carriers mark messages as spam. This article clarifies: - Why undelivered messages occur - What the Twilio error codes mean - How mobile carriers filter SMS content - What Sierra and clients can do to mitigate issues --- ### Understanding SMS Deliverability - Sierra integrates with Twilio to send individual and bulk text messages through the Dialer. - Twilio is a top provider of SMS services. - Deliverability issues are **not caused by Sierra or our account setup**. Even if multiple clients use Sierra numbers under the same Twilio account, this does **not** impact filtering. - Once a message leaves Sierra and Twilio, delivery is controlled by the mobile carrier. [back to the top](https://help.sierrainteractive.com/helpcenter/understanding-why-a-text-message-to-a-lead-shows-as-undelivered#top) #### **When a Message Is Marked “Undelivered”** - A message marked “Undelivered” appears in the lead detail page with a Twilio error code (e.g., 30003, 30004, etc.). - The system note includes the error code and a link to this article for context. #### **What the Twilio Error Codes Mean** | **30003** | Unreachable destination handset | | --- | --- | | **30004** | Message blocked | | **30005** | Unknown destination handset | | **30006** | Landline or unreachable carrier | | **30007** | Carrier violation | | **30008** | Unknown error | #### **Carrier Filtering Context** - Cell carriers actively filter commercial SMS, especially **high-volume or repetitive messages**. - Carriers do not provide detailed rules for filtering, and filtering is **outside Sierra and Twilio control**. - Filtering is often **per-message**, but once a number is flagged, future messages even unique ones may be more likely to be filtered. - Deliverability may fluctuate: the same lead can receive some messages successfully and others marked undelivered. [back to the top](https://help.sierrainteractive.com/helpcenter/understanding-why-a-text-message-to-a-lead-shows-as-undelivered#top) #### **Twilio Insights** - Repetitive or templated content can trigger classification as automated application-to-person (A2P) traffic. - Once a number is flagged by carriers, its reputation is impacted, increasing the likelihood of future undelivered messages. - Using short codes is **not recommended**: they are expensive and clients prefer local numbers to communicate with leads. #### **What Sierra Has Implemented** - The system displays the **error code** for undelivered messages on the lead detail page. - **Twilio Lookup** identifies the line type (mobile, landline, VOIP) when a lead is first routed through the system. - Lookup is applied automatically for all new messages if missing. - Manual imports or older leads may not have Lookup initially. - These measures provide visibility into undelivered messages and help avoid sending SMS to unsupported numbers. [back to the top](https://help.sierrainteractive.com/helpcenter/understanding-why-a-text-message-to-a-lead-shows-as-undelivered#top) --- ### Best Practices - Avoid repetitive or templated content in bulk SMS. - Space out messages, especially from new numbers. - Prioritize active leads and reduce unnecessary bulk sends. - Limit aggressive high-volume texting in short windows. - Rotate or replace Dialer numbers showing high undelivered rates (small forwarding fee applies). [back to the top](https://help.sierrainteractive.com/helpcenter/understanding-why-a-text-message-to-a-lead-shows-as-undelivered#top) --- ### Troubleshooting Common Issues - **High percentage of undelivered messages** Try retiring and forwarding from the affected Dialer number. Use a new number and reduce outbound SMS volume. - **Lead never receives texts despite appearing valid** Check the Line Type using Twilio Lookup in the lead detail. If it’s a landline or VOIP, SMS may not be supported. --- ### FAQs - **Is Sierra’s system causing messages to fail?** No. Messages leave Sierra and Twilio successfully. Delivery failures occur at the carrier level, based on filtering. - **Are we charged for filtered messages?** Yes. Twilio bills Sierra for every message sent, regardless of carrier filtering. - **Will all undelivered messages have an error code?** Yes. Sierra displays Twilio’s error codes in the system note. - **Can I mark a lead as opted out after an undelivered message?** No. Since many leads receive some messages successfully, auto-opting out would risk blocking real communication. [back to the top](https://help.sierrainteractive.com/helpcenter/understanding-why-a-text-message-to-a-lead-shows-as-undelivered#top) - [Getting Started with Sierra](https://help.sierrainteractive.com/helpcenter/getting-started-with-sierra?hsLang=en#main-content) - [Orientation & Approvals](https://help.sierrainteractive.com/helpcenter/getting-started-with-sierra?hsLang=en#orientation-approvals) - [Activate Your Sierra Dialer](https://help.sierrainteractive.com/helpcenter/getting-started-with-sierra?hsLang=en#activate-your-sierra-dialer) - [CRM Setup](https://help.sierrainteractive.com/helpcenter/getting-started-with-sierra?hsLang=en#crm-setup) - [Connect Your Data](https://help.sierrainteractive.com/helpcenter/getting-started-with-sierra?hsLang=en#connect-your-data) - [Launch Your Website](https://help.sierrainteractive.com/helpcenter/getting-started-with-sierra?hsLang=en#launch-your-website) - [Start Working with Leads](https://help.sierrainteractive.com/helpcenter/getting-started-with-sierra?hsLang=en#start-working-with-leads) - [Enhance Your Site](https://help.sierrainteractive.com/helpcenter/getting-started-with-sierra?hsLang=en#enhance-your-site) - [Video Resource Library](https://help.sierrainteractive.com/helpcenter/video-resource-library?hsLang=en#main-content) - [Webinar Recordings](https://help.sierrainteractive.com/helpcenter/video-resource-library?hsLang=en#webinar-recordings) - [Video FAQ](https://help.sierrainteractive.com/helpcenter/video-resource-library?hsLang=en#video-faq) - [IntelliSearch](https://help.sierrainteractive.com/helpcenter/video-resource-library?hsLang=en#intellisearch) - [Lead Generation & Capture](https://help.sierrainteractive.com/helpcenter/lead-generation-capture?hsLang=en#main-content) - [Sierra Digital Marketing Services](https://help.sierrainteractive.com/helpcenter/lead-generation-capture?hsLang=en#sierra-digital-marketing-services) - [Lead Tracking](https://help.sierrainteractive.com/helpcenter/lead-generation-capture?hsLang=en#lead-tracking) - [Saved Searches & IDX Settings](https://help.sierrainteractive.com/helpcenter/lead-generation-capture?hsLang=en#saved-searches-idx-settings) - [Email Marketing & Automation](https://help.sierrainteractive.com/helpcenter/lead-generation-capture?hsLang=en#email-marketing-automation) - [Lead Capture Tools](https://help.sierrainteractive.com/helpcenter/lead-generation-capture?hsLang=en#lead-capture-tools) - [IntelliSearch](https://help.sierrainteractive.com/helpcenter/lead-generation-capture?hsLang=en#intellisearch) - [Lead Engagement & Nurturing](https://help.sierrainteractive.com/helpcenter/lead-engagement-nurturing?hsLang=en#main-content) - [AI-Assisted Lead Engage](https://help.sierrainteractive.com/helpcenter/lead-engagement-nurturing?hsLang=en#ai-assisted-lead-engage) - [E-Alerts & Market Updates](https://help.sierrainteractive.com/helpcenter/lead-engagement-nurturing?hsLang=en#e-alerts-market-updates) - [Sierra Success Hub](https://help.sierrainteractive.com/helpcenter/lead-engagement-nurturing?hsLang=en#sierra-success-hub) - [Drip Campaigns](https://help.sierrainteractive.com/helpcenter/lead-engagement-nurturing?hsLang=en#drip-campaigns) - [Action Plans & Automations](https://help.sierrainteractive.com/helpcenter/lead-engagement-nurturing?hsLang=en#action-plans-automations) - [Buyer Lead Workflow](https://help.sierrainteractive.com/helpcenter/lead-engagement-nurturing?hsLang=en#buyer-lead-workflow) - [Bulk Actions](https://help.sierrainteractive.com/helpcenter/lead-engagement-nurturing?hsLang=en#bulk-actions) - [Lead Management](https://help.sierrainteractive.com/helpcenter/lead-management?hsLang=en#main-content) - [Lead Organization & Tagging](https://help.sierrainteractive.com/helpcenter/lead-management?hsLang=en#lead-organization-tagging) - [Reporting & Exports](https://help.sierrainteractive.com/helpcenter/lead-management?hsLang=en#reporting-exports) - [Platform Tools](https://help.sierrainteractive.com/helpcenter/lead-management?hsLang=en#platform-tools) - [Lead Routing & Permissions](https://help.sierrainteractive.com/helpcenter/lead-management?hsLang=en#lead-routing-permissions) - [Calling & Dialer Tools](https://help.sierrainteractive.com/helpcenter/lead-management?hsLang=en#calling-dialer-tools) - [Team Management & Accountability](https://help.sierrainteractive.com/helpcenter/lead-management?hsLang=en#team-management-accountability) - [Website Management](https://help.sierrainteractive.com/helpcenter/website-management?hsLang=en#main-content) - [Website Structure & Navigation](https://help.sierrainteractive.com/helpcenter/website-management?hsLang=en#website-structure-navigation) - [AI Visibility & SEO](https://help.sierrainteractive.com/helpcenter/website-management?hsLang=en#ai-visibility-seo) - [Website Pages & Content](https://help.sierrainteractive.com/helpcenter/website-management?hsLang=en#website-pages-content) - [DNS, Branding, & User Experience](https://help.sierrainteractive.com/helpcenter/website-management?hsLang=en#dns-branding-user-experience) - [Analytics](https://help.sierrainteractive.com/helpcenter/website-management?hsLang=en#analytics) - [Support & Account Help](https://help.sierrainteractive.com/helpcenter/support-account-help?hsLang=en#main-content) - [Contact Support](https://help.sierrainteractive.com/helpcenter/support-account-help?hsLang=en#contact-support) - [Billing & Account Changes](https://help.sierrainteractive.com/helpcenter/support-account-help?hsLang=en#billing-account-changes) - [Access & Permissions](https://help.sierrainteractive.com/helpcenter/support-account-help?hsLang=en#access-permissions) - [Industry & MLS Compliance](https://help.sierrainteractive.com/helpcenter/industry-mls-compliance?hsLang=en#main-content) - [NAR](https://help.sierrainteractive.com/helpcenter/industry-mls-compliance?hsLang=en#nar) - [Compliance and Best Practices](https://help.sierrainteractive.com/helpcenter/industry-mls-compliance?hsLang=en#compliance-and-best-practices) - [Integrations & API](https://help.sierrainteractive.com/helpcenter/integrations-api?hsLang=en#main-content) - [Communication Integrations](https://help.sierrainteractive.com/helpcenter/integrations-api?hsLang=en#communication-integrations) - [Marketing Integrations](https://help.sierrainteractive.com/helpcenter/integrations-api?hsLang=en#marketing-integrations) - [CRM Integrations](https://help.sierrainteractive.com/helpcenter/integrations-api?hsLang=en#crm-integrations) - [API & Developer Tools](https://help.sierrainteractive.com/helpcenter/integrations-api?hsLang=en#api-developer-tools) - [Calendar & Appointments](https://help.sierrainteractive.com/helpcenter/integrations-api?hsLang=en#calendar-appointments) [![Sierra Interactive logo](https://help.sierrainteractive.com/hs-fs/hubfs/sierra%20interactive%20logo.png?width=250&height=34&name=sierra%20interactive%20logo.png "Sierra Interactive logo")](https://help.sierrainteractive.com/helpcenter?hsLang=en) 1205 E Washington St #110, Louisville, KY 40206 Copyright © 2025, Sierra Interactive