System Email Error - The account you signed in with does not have permission

#2 means that you must be signing into the sign in page with the same account as you are using for the system email address. If you’re using postmaster@domain.com as the system email address, sign into the sign in page with postmaster@domain.com.

A shared Office365 mailbox (which does not need to be licensed) only works because it is delegated to other paying users. Since delegation apparently cannot be used in this process, you won’t be able to use a shared mailbox as a system email account.

Thanks a lot.  Our customer says he signed in with the same account used for the system email address. But still, we get this error. Any idea what the issue could be?

Fraid not 🙄

Thanks 🙂

The error in trace says, 

Error: The mail receive has failed.
Emails cannot be received because the account you signed in with does not have permission for using the email address specified in the system email account on the System Email Accounts (SM204002) form.

PX.Common.IMAP.Client.ImapClientException: BAD User is authenticated but not connected.

Thank you very much! yes the account’s IMAP was disabled.

We have few other similar accounts, but they are still not working, gives the same error regardless enabling IMAP.

Have you started from the beginning for each mailbox, configuring the external application and such, for each one?

Yes I did. The error I get is the same as before. 

The error in trace says, 

Error: The mail receive has failed.
Emails cannot be received because the account you signed in with does not have permission for using the email address specified in the system email account on the System Email Accounts (SM204002) form.

PX.Common.IMAP.Client.ImapClientException: BAD User is authenticated but not connected.

FYI, make sure the user account has a license assigned to it in M365. We had the same error, but it was due to the mailbox not having a license assigned.