504 Gateway Timeout
Situations in the vault where SharePoint, SPFx, Microsoft Graph or the Azure services around them answer with HTTP 504. Each one explains why it happens and how to fix it.
- /me/sendMail from an account without a mailbox can time out with 504 – and the Graph SDK retries it three more timesgotchas / graphNo MailboxNotEnabled error, just a 504 after ~30 s; the SDK RetryHandler repeats the non-idempotent POST up to 3×, so the button hangs ~2 min and a late success can send duplicates; check assignedPlans for an enabled…