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Gmail provides features to debug common issues with dynamic emails.
Enable the Fallback Debugging Banner in Gmail Web
Developers can enable a debugging banner to determine why their emails aren't
rendering as AMP emails. The banner informs you that the AMP part of your email
isn't being rendered and provides a reason why. More information on each of the
reasons can be found in the following section.
In order to enable the debugging banner for a specific email, you must whitelist
the sender's address in your developer settings and then refresh the page. Refer
toTest your AMP emails in
Gmailfor more
information.
Fallback Reasons
These are some of the common reasons that dynamic emails fail to render and
instead fall back to the to basic text or HTML.
Fallback Reasons
ACCOUNT_TYPE
Dynamic emails aren't supported by your account type. Try using a new
test Gmail account to view the email.
The email wasautomatically forwardedfrom a different account. For emails to render AMP content, make sure
you open the email with the account it was sent to.
BROWSER_ERROR
Something unexpected happened. Ensure you're using one of thesupported browsersand
try again.
DKIM_FAILED
The email failed Domain Keys Identified Mail (DKIM) authentication. See
theauthentication requirementsfor more information.
DKIM_NOT_MATCHING_FROM
The email failed Domain Keys Identified Mail (DKIM)alignment.
DYNAMIC_EMAIL_DISABLED
Dynamic emails are disabled. Ensure thatDynamic emailhas been
enabled in the Gmail settings panel.
HIDING_IMAGES
TheAlways display external imagessetting is disabled. Re-enable
this setting in the settings panel and refresh the page.
The client needs to be refreshed. If you're using the web client and
haven't enabled offline mode, refresh the page normally. If you have
enabled offline mode, a hard refresh is required. If you're using a
mobile app, try clearing app data and relaunching the app.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-28 UTC."],[],[],null,["# Debug Dynamic Emails\n\nGmail provides features to debug common issues with dynamic emails.\n\nEnable the Fallback Debugging Banner in Gmail Web\n-------------------------------------------------\n\nDevelopers can enable a debugging banner to determine why their emails aren't\nrendering as AMP emails. The banner informs you that the AMP part of your email\nisn't being rendered and provides a reason why. More information on each of the\nreasons can be found in the following section.\n\nIn order to enable the debugging banner for a specific email, you must whitelist\nthe sender's address in your developer settings and then refresh the page. Refer\nto [Test your AMP emails in\nGmail](/workspace/gmail/ampemail/testing-dynamic-email) for more\ninformation.\n| **Note:** The banner doesn't appear if you have disabled dynamic email in the settings panel. If you don't see the banner, ensure that you have enabled the setting and refresh the page.\n\nFallback Reasons\n----------------\n\nThese are some of the common reasons that dynamic emails fail to render and\ninstead fall back to the to basic text or HTML.\n\n| Fallback Reasons ||\n|-----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| `ACCOUNT_TYPE` | Dynamic emails aren't supported by your account type. Try using a new test Gmail account to view the email. |\n| `AUTH_FAILED` | The email failed one of the [authentication requirements](/workspace/gmail/ampemail/security-requirements#sender_authentication). |\n| `AUTO_FORWARDED` | The email was [automatically forwarded](https://support.google.com/mail/answer/10957) from a different account. For emails to render AMP content, make sure you open the email with the account it was sent to. |\n| `BROWSER_ERROR` | Something unexpected happened. Ensure you're using one of the [supported browsers](/workspace/gmail/ampemail/supported-browsers) and try again. |\n| `DKIM_FAILED` | The email failed Domain Keys Identified Mail (DKIM) authentication. See the [authentication requirements](/workspace/gmail/ampemail/security-requirements#sender_authentication) for more information. |\n| `DKIM_NOT_MATCHING_FROM` | The email failed Domain Keys Identified Mail (DKIM) [alignment](/workspace/gmail/ampemail/security-requirements#dkim_alignment). |\n| `DYNAMIC_EMAIL_DISABLED` | Dynamic emails are disabled. Ensure that **Dynamic email** has been enabled in the Gmail settings panel. |\n| `HIDING_IMAGES` | The **Always display external images** setting is disabled. Re-enable this setting in the settings panel and refresh the page. |\n| `INTERNAL_ERROR` | Something unexpected happened in Gmail. |\n| `INVALID_AMP` | The AMP was invalid. See the AMP for Email spec for more information and follow the [steps to validate an AMP email](https://amp.dev/documentation/guides-and-tutorials/learn/validation-workflow/validate_emails/?format=email). |\n| `MALFORMED` | The email contains more than one `text/x-amp-html` part or no fallback `text/html` or `text/plain` part. See [the delivery requirements](/workspace/gmail/ampemail/testing-dynamic-email#delivery_requirements) for more information. |\n| `MESSAGE_CLIPPED` | The email's `text/x-amp-html` part is too long. See the [delivery requirements](/workspace/gmail/ampemail/testing-dynamic-email) for more information. |\n| `NOT_AVAILABLE_ON_PLATFORM` | The sender has disabled dynamic content on this platform. If you are using the web client, try viewing the email on mobile. |\n| `NOT_MAIN_WINDOW` | The email was opened in a new window. Try opening this email in the main Gmail window. |\n| `OFFLINE` | The client is offline. Check your internet connection and try again. |\n| `OLD_EMAIL` | The email was sent over 30 days ago. |\n| `PHISHY` | The email was marked as phishing. Ensure that your email follows the [security requirements and email best practices](https://support.google.com/mail/answer/81126). |\n| `REFRESH_REQUIRED` | The client needs to be refreshed. If you're using the web client and haven't enabled offline mode, refresh the page normally. If you have enabled offline mode, a hard refresh is required. If you're using a mobile app, try clearing app data and relaunching the app. |\n| `SPAM` | The email was marked as spam. Ensure that your email follows the [security requirements and email best practices](https://support.google.com/mail/answer/81126). |\n| `SPF_FAILED` | The email failed Sender Policy Framework (SPF) authentication. See the [authentication requirements](/workspace/gmail/ampemail/security-requirements#sender_authentication) for more information. |\n| `SUSPICIOUS` | The email seems suspicious. Ensure that your email follows the [security requirements and email best practices](https://support.google.com/mail/answer/81126). |\n| `THREAD_TOO_LONG` | The reply chain has become too long. Dynamic content is only rendered for the last 10 messages in a thread. |\n| `TIMEOUT` | The dynamic content took too long to load. Check your internet connection and try again. |\n| `TLS_ENCRYPTION` | The email wasn't TLS encrypted. See [the TLS security requirement](/workspace/gmail/ampemail/security-requirements#tls_encryption) for more information and resend the email with TLS. |\n| `TRANSLATED` | Translation is enabled for the email. Disable automatic translation in Gmail and try again. |\n| `WRONG_VERSION` | Dynamic content isn't supported on your device. See the list of [supported browsers](/workspace/gmail/ampemail/supported-browsers) for more information. |"]]
