Summary
The error message "Authenticated user is not authorized to send mail" when using the GSuite API indicates a specific issue with authorization, rather than email deliverability itself. While the user's credentials (authentication) are accepted, the account lacks the necessary permissions to send email via the API endpoint. This means that emails sent through the API are not being transmitted, even if regular email clients or the web interface might still work. This issue often points to policy violations, account suspension, or misconfigured API access within Google Workspace. Understanding this distinction is key to resolving the problem effectively.
Key findings
- Authorization failure: The error specifically means the authenticated user (or service account) does not have the permission to send email through the Google Workspace API, not that the authentication itself failed (a 401 code might mistakenly be used instead of a 403).
- API-specific issue: This problem is typically confined to emails sent via the GSuite API and does not necessarily affect emails sent through standard Gmail web clients or other mail applications.
- Policy violation: The most common reason for this restriction is that the account has violated Google's terms of service, often due to sending unsolicited or high volumes of emails, leading to an API sending suspension. You can learn more about this in our guide on how to fix GSuite sender reputation issues.
- Compromised accounts/plugins: The issue could also stem from a compromised website or a problematic third-party plugin (e.g., WordPress) that is leveraging the API to send unauthorized or spammy emails.
Key considerations
- Contact google support: The primary course of action is to contact Google Workspace support with the full error message for direct diagnosis and resolution. They can provide specific details about the account's sending restrictions.
- Review API usage: Investigate how the GSuite API is being used. Determine if any third-party services, lead generation companies, or website plugins are sending emails on behalf of the domain, and check their sending practices.
- Check permissions: Ensure that the specific user or service account configured for the API has the necessary sending permissions enabled within Google Workspace administrative settings. This often involves checking OAuth2 scopes and ensuring proper authorization as discussed in the Gmail API authentication and authorization guide.
- Verify DMARC policy: While not directly causing this API error, a lax DMARC policy (e.g., p=none) might indicate broader issues that could lead to abuse or spoofing, which in turn could trigger Google's restrictions. Consider moving towards a stronger policy as outlined in our guide on how to safely transition your DMARC policy.
What email marketers say
Email marketers and developers encountering the "Authenticated user is not authorized to send mail" error often find it perplexing because authentication appears to pass, yet sending fails. Their experiences highlight the confusion between successful login and the distinct lack of proper permissions for email sending via the GSuite API. Many suspect the root cause to be policy violations due to the nature of their email sending activities, or misconfigured API keys, rather than traditional deliverability problems.
Key opinions
- API authentication vs. authorization: Marketers frequently mistake successful API login for having permission to send emails, not realizing that authorization is a separate layer.
- Impact of external services: Concerns arise that third-party lead generation services or website plugins might be misusing the GSuite API, leading to the account being flagged for spamming by Google.
- Unintended policy violations: Some marketers believe they are not maliciously spamming but might be inadvertently violating Google's terms of service due to their chosen sending methods or software, leading to restrictions.
- Limited visibility from DMARC: While DMARC reports provide valuable insights into email authentication, they may not fully expose the specific nature of API abuse leading to a sending restriction, particularly if volume is low or policies are not enforced. Understanding DMARC reports from Google and Yahoo is still important for overall deliverability health.
Key considerations
- Investigate third-party integrations: Carefully examine any services or plugins connected to the GSuite API for their email sending practices, especially if they handle lead generation or appointment confirmations.
- Educate on API permissions: For small businesses or individuals without dedicated IT support, it's crucial to understand the difference between authenticating an API and authorizing specific actions like sending mail. This distinction is paramount in avoiding errors like "Authenticated user is not authorized to send mail" when using the GSuite API. For general authentication issues, refer to why Gmail cannot verify authenticated email.
- Check for website compromises: If a website has been previously compromised (e.g., WordPress hacks), it's possible it could be secretly sending spam via the API, even if the primary user is unaware. This can lead to the API's sending ability being revoked, requiring a thorough security audit.
- Seek direct support: When facing such a direct error message from Google, the most effective path to resolution is usually through Google's own support channels, providing them with the exact error log.
Marketer view
Email Marketer from Email Geeks observed a friend receiving an error message, "Authenticated user is not authorized to send mail," and was trying to understand its meaning. The marketer initially found the message confusing, as they weren't sure if emails were still being delivered despite the error. This situation highlights the common challenge users face when deciphering technical API responses.The marketer noted that they did receive an email from their friend, leading to the assumption that some emails were still going out. This suggests a potential disconnect where some email sending methods might work while API-driven sending is blocked, adding to the confusion. This scenario underscores the need for clear diagnostic information.
Marketer view
Email Marketer from Email Geeks suggested that their friend, who runs a small website without dedicated IT support, might be the unintentional cause of the issue. They pondered whether the friend could be sending out cold emails, which might have led Google to revoke their API sending ability.The marketer also considered the possibility of domain spoofing, although the friend had DMARC enabled (albeit at p=none). This suspicion leans towards cold emails being the primary reason for the block, particularly given a past incident where the WordPress site was hacked and flagged as suspicious by Norton, indicating potential vulnerabilities.
What the experts say
Experts universally agree that the error "Authenticated user is not authorized to send mail" is an API authorization issue, not a traditional email deliverability problem. While authentication might succeed, the GSuite account's permission to send via the API has been revoked. This often occurs due to violations of Google's terms of service, typically involving spamming or sending practices deemed abusive, even if unintentional. They emphasize that Google's threshold for such action is quite high, suggesting a significant breach has occurred.
Key opinions
- Not a deliverability issue: The consensus is that this error is a server-side API response, indicating a lack of permission to send email through that specific channel, rather than a problem with email reaching the inbox or being blocked by recipient servers. It's about the sender's own system refusing the mail.
- API abuse is the cause: Experts strongly suspect that the GSuite account is being used for spamming, or at least for sending mail in a way that violates Google's policies, leading to the API sending capability being shut down.
- High threshold for Google's action: Google's systems typically have a high tolerance before revoking API sending permissions, implying that the abusive activity was significant or consistent.
- Distinction from regular email: The account may still be able to send emails via the GSuite web application or standard email clients, as the restriction specifically applies to the API endpoint. For broader issues related to GSuite emails landing in spam, see our guide on why Icelandic domains using Gsuite land in spam.
- Potential for compromise: A compromised website (e.g., via a WordPress plugin) could be silently using the GSuite API to send spam, leading to this restriction without the user's direct knowledge.
Key considerations
- Direct google support: The most effective way to resolve this is to contact Google Workspace support with the full error log, as they are the only ones who can provide specific reasons for the API restriction and potential remedies.
- Audit API usage: Thoroughly investigate all applications, services, and plugins that use the GSuite API to send emails. Identify any that might be sending unsolicited or high-volume messages. This is similar to troubleshooting email authentication issues with HR systems.
- Review account permissions: Check that the specific account or service identity attempting to send email via the API has the proper permissions and scopes enabled. Service accounts, in particular, may require domain-wide delegation for impersonation to send emails. Google Cloud provides comprehensive documentation on authentication methods.
- Address underlying causes: Even if the user is unaware, engaging in practices like cold email sending or using services that do so can lead to this block. It's a teachable moment to shift towards compliant email sending practices.
Expert view
Expert from Email Geeks clarified that the issue is an API response indicating a broken authentication setup. This means the smart host, or sending server, is actively refusing to transmit the email because it doesn't recognize the sending authorization.The expert further emphasized that this is not an email deliverability issue in the traditional sense, but rather a problem with the outgoing server's refusal to send. This distinction is important for troubleshooting, as it directs efforts to API permissions and account status rather than broader sender reputation or inbox placement factors.
Expert view
Expert from Email Geeks explained that the error means the user has successfully logged into the API, but the specific user account (or service account) they are logged in as does not possess the necessary permissions to send email. This points to a granular permissions issue rather than a complete failure to authenticate.They stressed that this problem is not directly email-related but is tied to the service's configuration. Therefore, it requires someone familiar with the specific service being used to diagnose it, likely through opening a support issue with Google.
What the documentation says
Official documentation from Google and related technical communities provides direct explanations for the "Authenticated user is not authorized to send mail" error. These sources confirm that the error stems from authorization failures, such as expired or revoked access tokens, or insufficient permissions granted to the API key or service account. They distinguish this from authentication errors, highlighting that the user's identity is recognized, but their right to perform the specific action (sending mail) is denied within the API's scope. The emphasis is on correctly configuring permissions and understanding the nuances of OAuth2 and service account delegation.
Key findings
- Expired or revoked access tokens: Google documentation explicitly states this error can occur when an access token from the Google Authorization Server has expired or been revoked.
- Permission-based denial: The error (often 403 Forbidden, though sometimes incorrectly seen as 401 Unauthorized) indicates a permission issue preventing the Gmail API from performing the requested action, even if authentication succeeded.
- Service account limitations: Service accounts may require specific configurations, such as OAuth2 with domain-wide delegation, to be authorized to impersonate users and send emails.
- Distinction between authentication and authorization: Authentication verifies identity, while authorization verifies access to resources. This error is a clear authorization failure, implying that the identity is known, but the permissions are insufficient.
Key considerations
- Update API key permissions: The solution often involves updating the permissions for the API key or service account generated for the email provider within Google Workspace's settings.
- Enable domain-wide delegation: For service accounts, ensuring domain-wide delegation is enabled is critical if the service account needs to impersonate a user to send emails. This process is detailed in Google's documentation, specifically in the service accounts overview.
- Review OAuth2 setup: If using OAuth2, confirm that the correct scopes are requested and granted, particularly those related to sending mail. Issues with the authentication process itself are often covered in Google's troubleshooting guides, such as the Gmail API authentication troubleshooter.
- Check for account-level Gmail settings: Verify that Gmail sending capabilities are not disabled for the specific user or service account within the Google Workspace admin console.
Technical article
Google for Developers states that the error "Authenticated user is not authorized to send mail" occurs when an access token from the Google Authorization Server has either expired or been revoked. This indicates a problem with the validity or status of the token used to grant permissions.Developers should implement proper token management, including refreshing tokens before expiration and handling revocation gracefully. This ensures continuous authorization for API calls, preventing interruptions in email sending.
Technical article
Auth0 Community suggests resolving the error by updating the permissions for the API key generated in your External SMTP Provider or Custom Email Provider. This implies that while the key may be correctly authenticated, its associated permissions might be insufficient for the desired action.This highlights the importance of granular permission settings. Users must ensure that the scope granted to the API key specifically includes the ability to send emails, rather than just basic access or other administrative functions.
Related resources
7 resources
Related pages
Why are emails sent via an HR system connected to Gmail landing in spam despite authentication passing?
How to fix Gsuite sender reputation issues when business emails are sent to quarantine in Outlook?
Why does Gmail say it cannot verify my authenticated email?
What is the best way to authenticate with Gmail Postmaster API using OAuth 2.0?
How to fix common DMARC issues in Microsoft 365 and Google Workspace
A simple guide to DMARC, SPF, and DKIM
Why Your Emails Are Going to Spam in 2024 and How to Fix It
Ultimate Guide to Google Postmaster Tools V2
