https://graph.microsoft.com/v1.0/me/sendMail keeps giving 503 or 504 response

Question

Hello,

I am encountering an issue with the Microsoft Graph API when attempting to send emails using the /me/sendMail endpoint. These requests frequently fail with either a 503 Service Unavailable or 504 Gateway Timeout response. While the requests occasionally succeed, the majority fail. This behavior began today, the endpoint has worked without any issues prior to this.

Details:
Data Center: Norway East

X-MS-AGS-Diagnostic: {"ServerInfo":{"DataCenter":"Norway East","Slice":"E","Ring":"2","ScaleUnit":"000","RoleInstance":"OSL0EPF00000B98"}}

Answer 1

Hello Alexander!
503 occurs when the service is temporarily unavailable for maintenance or is overloaded.
Ensure that you have implemented a retry mechanism. It could be due to throttling/overload by either your client and in that case check for best practices here-https://learn.microsoft.com/en-us/graph/throttling#best-practices-to-avoid-throttling

Error Codes doc-https://learn.microsoft.com/en-us/graph/errors#http-status-codes