{"id":15801,"date":"2026-02-10T13:32:45","date_gmt":"2026-02-10T13:32:45","guid":{"rendered":"https:\/\/www.k12insight.com\/kc\/?p=15801"},"modified":"2026-02-10T13:37:04","modified_gmt":"2026-02-10T13:37:04","slug":"twilio-troubleshooting","status":"publish","type":"post","link":"https:\/\/www.k12insight.com\/kc\/how-to-articles\/twilio-troubleshooting\/","title":{"rendered":"Twilio Troubleshooting"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-post\" data-elementor-id=\"15801\" class=\"elementor elementor-15801\" data-elementor-post-type=\"post\">\n\t\t\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-555d788a elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"555d788a\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-34d51464\" data-id=\"34d51464\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-542b271b elementor-widget elementor-widget-text-editor\" data-id=\"542b271b\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<section class=\"twilio-troubleshooting-guide\">\n\n  <!-- TABLE OF CONTENTS -->\n  <nav class=\"twilio-toc\">\n    <h3>Table of Contents<\/h3>\n    <ol>\n      <li><a href=\"#mandatory-connectivity-test\">Mandatory Connectivity Test (Step 1)<\/a><\/li>\n      <li>\n        <a href=\"#firewall-network-requirements\">Firewall &amp; Network Requirements (Mandatory)<\/a>\n        <ol>\n          <li><a href=\"#required-ports-protocols\">Required Ports &amp; Protocols<\/a><\/li>\n          <li><a href=\"#required-domains\">Required Domains (FQDNs)<\/a><\/li>\n        <\/ol>\n      <\/li>\n      <li><a href=\"#ngfw-app-id\">Next-Generation Firewall (App-ID) Configuration<\/a><\/li>\n      <li><a href=\"#common-misconfigurations\">Common Misconfigurations to Check<\/a><\/li>\n      <li><a href=\"#tests-still-fail\">If Tests Still Fail<\/a><\/li>\n      <li><a href=\"#quick-validation-checklist\">Quick Validation Checklist (For IT Teams)<\/a><\/li>\n      <li><a href=\"#summary\">Summary<\/a><\/li>\n    <\/ol>\n  <\/nav>\n<br>\n  <hr><br>\n\n  <!-- MAIN CONTENT -->\n  <h2 id=\"twilio-troubleshooting-guide\">Twilio Connectivity \u2013 Troubleshooting Guide<\/h2>\n\n  <p><strong>Audience:<\/strong> IT, Network, and Firewall Teams<\/p>\n  <p><strong>Purpose:<\/strong> Validate network readiness for <strong>Twilio Voice<\/strong> and <strong>WebRTC services<\/strong>.<\/p>\n<br>\n  <hr>\n<br>\n  <h3 id=\"mandatory-connectivity-test\">1. Mandatory Connectivity Test (Step 1)<\/h3>\n\n  <p>All customers must run the official <strong>Twilio WebRTC diagnostics test<\/strong>.<\/p>\n\n  <p>\n    \ud83d\udd17 <strong>Test URL:<\/strong><br>\n    \ud83d\udc49 <a href=\"https:\/\/networktest.twilio.com\/\" target=\"_blank\" rel=\"noopener noreferrer\">\n      https:\/\/networktest.twilio.com\/\n    <\/a>\n  <\/p>\n\n  <h4>Expected Result<\/h4>\n  <p><strong>ALL tests must show <span style=\"color:green;\">PASS<\/span><\/strong>, especially:<\/p>\n\n  <ul>\n    <li>TURN UDP Connectivity<\/li>\n    <li>Voice Test (PCMU)<\/li>\n    <li>Voice Test (Opus)<\/li>\n  <\/ul>\n\n  <h4>If ALL Tests Pass<\/h4>\n  <p>\u2705 Network connectivity is <strong>NOT<\/strong> the issue.<br>\n  Proceed to <strong>application-level troubleshooting<\/strong>.<\/p>\n\n  <h4>If ANY Test Fails<\/h4>\n  <p>\u274c A network firewall or security policy is blocking Twilio traffic.<br>\n  Proceed to <strong>Section 2 \u2013 Firewall Validation<\/strong>.<\/p>\n\n  <br><hr><br>\n\n  <h3 id=\"firewall-network-requirements\">2. Firewall &amp; Network Requirements (Mandatory)<\/h3>\n\n  <h4 id=\"required-ports-protocols\">2.1 Required Ports &amp; Protocols<\/h4>\n\n  <p>Ensure the following <strong>outbound traffic<\/strong> is allowed:<\/p>\n\n  <table border=\"1\" cellpadding=\"8\" cellspacing=\"0\" width=\"100%\">\n    <thead>\n      <tr>\n        <th>Protocol<\/th>\n        <th>Port(s)<\/th>\n        <th>Purpose<\/th>\n      <\/tr>\n    <\/thead>\n    <tbody>\n      <tr>\n        <td>TCP<\/td>\n        <td>443<\/td>\n        <td>HTTPS, TLS signaling<\/td>\n      <\/tr>\n      <tr>\n        <td>UDP<\/td>\n        <td>3478<\/td>\n        <td>STUN<\/td>\n      <\/tr>\n      <tr>\n        <td>UDP<\/td>\n        <td>5349<\/td>\n        <td>TURN<\/td>\n      <\/tr>\n      <tr>\n        <td>UDP<\/td>\n        <td>10000\u201320000<\/td>\n        <td>Twilio media (RTP audio)<\/td>\n      <\/tr>\n    <\/tbody>\n  <\/table>\n\n  <h4 id=\"required-domains\">2.2 Required Domains (FQDNs)<\/h4>\n\n  <p>Allow outbound access to:<\/p>\n  <ul>\n    <li><code>*.twilio.com<\/code><\/li>\n  <\/ul>\n\n  <p>If your firewall requires explicit FQDN allow-listing, ensure <strong>wildcard support<\/strong> is enabled.<\/p>\n\n <br> <hr><br>\n\n  <h3 id=\"ngfw-app-id\">3. Next-Generation Firewall (App-ID) Configuration<\/h3>\n\n  <p>For Palo Alto, Fortinet, Check Point, Sophos, or other NGFWs, ensure <strong>Application-ID rules<\/strong> are not blocking Twilio traffic.<\/p>\n\n  <table border=\"1\" cellpadding=\"8\" cellspacing=\"0\" width=\"100%\">\n    <thead>\n      <tr>\n        <th>App-ID<\/th>\n        <th>Role in Twilio \/ WebRTC<\/th>\n      <\/tr>\n    <\/thead>\n    <tbody>\n      <tr><td>dtls<\/td><td>Key exchange for SRTP encryption<\/td><\/tr>\n      <tr><td>stun<\/td><td>NAT traversal &amp; ICE negotiation<\/td><\/tr>\n      <tr><td>rtp<\/td><td>Real-time media transport<\/td><\/tr>\n      <tr><td>rtcp<\/td><td>Media control traffic<\/td><\/tr>\n      <tr><td>webrtc<\/td><td>Covers DTLS, RTP, STUN<\/td><\/tr>\n      <tr><td>ssl<\/td><td>HTTPS \/ TLS signaling<\/td><\/tr>\n      <tr><td>web-browsing<\/td><td>Twilio Console \/ browser UI<\/td><\/tr>\n      <tr><td>dns<\/td><td>Domain name resolution<\/td><\/tr>\n      <tr><td>sip (optional)<\/td><td>Only for SIP Trunking \/ BYOC<\/td><\/tr>\n    <\/tbody>\n  <\/table>\n\n  <p><strong>\ud83d\udd10 Best Practice:<\/strong><br>\n  Allow <strong>App-ID + Port-based rules together<\/strong>. App-ID detection may fail on encrypted traffic; ports provide fallback.<\/p>\n\n <br> <hr><br>\n\n  <h3 id=\"common-misconfigurations\">4. Common Misconfigurations to Check<\/h3>\n\n  <ul>\n    <li>\u274c UDP traffic blocked (most common issue)<\/li>\n    <li>\u274c RTP ports restricted or incorrectly narrowed<\/li>\n    <li>\u274c STUN \/ TURN App-ID blocked<\/li>\n    <li>\u274c SSL inspection breaking DTLS \/ WebRTC<\/li>\n    <li>\u274c Outdated Twilio IP or FQDN allow-list<\/li>\n  <\/ul>\n\n<br>  <hr><br>\n\n  <h3 id=\"tests-still-fail\">5. If Tests Still Fail<\/h3>\n\n  <ul>\n    <li>Firewall logs showing blocked traffic<\/li>\n    <li>Destination IP \/ FQDN<\/li>\n    <li>Port and protocol<\/li>\n    <li>App-ID (if applicable)<\/li>\n  <\/ul>\n\n  <p><strong>Confirm:<\/strong><\/p>\n  <ul>\n    <li>Outbound UDP allowed<\/li>\n    <li>No SSL inspection on WebRTC traffic<\/li>\n    <li>Twilio FQDNs or IPs in policy<\/li>\n  <\/ul>\n\n <br> <hr><br>\n\n  <h3 id=\"quick-validation-checklist\">6. Quick Validation Checklist (For IT Teams)<\/h3>\n\n  <ul>\n    <li>\u2705 Twilio Network Test \u2192 All PASS<\/li>\n    <li>\u2705 TCP 443 outbound allowed<\/li>\n    <li>\u2705 UDP 3478 &amp; 5349 allowed<\/li>\n    <li>\u2705 UDP 10000\u201320000 allowed<\/li>\n    <li>\u2705 <code>*.twilio.com<\/code> allowed<\/li>\n    <li>\u2705 STUN \/ DTLS \/ RTP \/ WebRTC App-IDs not blocked<\/li>\n    <li>\u2705 No SSL decryption for WebRTC<\/li>\n  <\/ul>\n\n <br> <hr>\n<br>\n  <h3 id=\"summary\">7. Summary<\/h3>\n\n  <ul>\n    <li>Twilio requires <strong>UDP<\/strong> for voice quality<\/li>\n    <li>All tests must <strong>PASS<\/strong> on the Twilio network test page<\/li>\n    <li>Most failures are caused by firewall <strong>App-ID or UDP restrictions<\/strong><\/li>\n    <li>Use <strong>Port + App-ID rules together<\/strong> for best results<\/li>\n  <\/ul>\n<br>\n<\/section>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>Table of Contents Mandatory Connectivity Test (Step 1) Firewall &amp; Network Requirements (Mandatory) Required Ports &amp; Protocols Required Domains (FQDNs) Next-Generation Firewall (App-ID) Configuration Common Misconfigurations to Check If Tests Still Fail Quick Validation Checklist (For IT Teams) Summary Twilio Connectivity \u2013 Troubleshooting Guide Audience: IT, Network, and Firewall Teams Purpose: Validate network readiness for...<\/p>\n","protected":false},"author":27,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"video","meta":{"inline_featured_image":false,"_kad_post_transparent":"default","_kad_post_title":"default","_kad_post_layout":"default","_kad_post_sidebar_id":"","_kad_post_content_style":"default","_kad_post_vertical_padding":"default","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"footnotes":""},"categories":[409],"class_list":["post-15801","post","type-post","status-publish","format-video","hentry","category-how-to-articles","tag-basic-telephony","tag-call-center","post_format-post-format-video"],"_links":{"self":[{"href":"https:\/\/www.k12insight.com\/kc\/wp-json\/wp\/v2\/posts\/15801","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.k12insight.com\/kc\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.k12insight.com\/kc\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.k12insight.com\/kc\/wp-json\/wp\/v2\/users\/27"}],"replies":[{"embeddable":true,"href":"https:\/\/www.k12insight.com\/kc\/wp-json\/wp\/v2\/comments?post=15801"}],"version-history":[{"count":5,"href":"https:\/\/www.k12insight.com\/kc\/wp-json\/wp\/v2\/posts\/15801\/revisions"}],"predecessor-version":[{"id":15820,"href":"https:\/\/www.k12insight.com\/kc\/wp-json\/wp\/v2\/posts\/15801\/revisions\/15820"}],"wp:attachment":[{"href":"https:\/\/www.k12insight.com\/kc\/wp-json\/wp\/v2\/media?parent=15801"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.k12insight.com\/kc\/wp-json\/wp\/v2\/categories?post=15801"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}