ErrorQuotaExceeded when sending from Shared Mailbox

Question

I've got a web app which uses Microsoft Graph API To send emails from a shared mailbox but is currently having some problems.

I use the following permissions ['user.read', 'mail.readwrite', 'mail.readwrite.shared', 'mail.send', 'mail.send.shared'] that are granted by the user on logging and the shared mail box is called with the https://graph.microsoft.com/v1.0/users/[shared-mail] url.

Before yesterday the emails were being sent, I can see the emails on the shared mailbox inbox (/mailFolders/inbox/messages?$top=50) and move them to different folders (messages/[id]/move).

My users can still send from their outlook apps emails as the shared mailbox without problems.

When using the Microsoft Graph Explorer or my web app, the error is also showing which leads me to think it's only happening when calling the MSGraph API.

When I call https://graph.microsoft.com/v1.0/users/[sharedMail]/sendMail, I get a 403 - Forbidden back:

{
  "error": {
    "code": "ErrorQuotaExceeded",
    "message": "Cannot submit message."
  }
}

Some guesses I've got are:

• There exists some kind of limit when sending email from Microsoft Graph API that I have reached (which is unlikely because there is usually only 40 emails per day).

• I need another permission scope to be able to send using the explorer and shared mailboxes.

Does anyone know if there is any problem with my configuration or the way I'm handling shared mailboxes send?

Answer 1

The error implies that the mailbox has exceeded its storage quota. The quota gets configured in Exchange. See Configure storage quotas for a mailbox for details on how to set/change a mailbox's quota.