Overview
This error indicates that the authentication attempt was rejected by the email server because the specified authentication type was not recognized or supported. It typically occurs during the initial connection phase when the SMTP server receives an OAuth 2.0 request but does not accept the authentication method.
Event example
See an example of the OAuth2 request failed Event message:
- Task "Daily Invoices" Action "Send Email" error: OAuth2 request failed (504 5.7.4 Unrecognized authentication type).
Cause
The most common causes of this error include:
- The SMTP server does not support OAuth 2.0 authentication or a wrong SMTP server address or port was specified.
- The server expects basic authentication, but OAuth 2.0 was attempted.
Solution
Confirm that the email provider and server support OAuth 2.0 for SMTP.
- Double-check the SMTP server address and port · Configurations for popular email services.
- If your email provider does not support OAuth 2.0, consider using app passwords or another supported Auth method.
- Ensure that the OAuth 2.0 credentials are valid and correctly initialized using the Sign-in button (again, when necessary).
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