I'm still having the same issue. Here is what I've done
I have deleted all rows from tabke
ost_email_account & reconfigured my email.
After I select
Same As Remote Mailbox , I receive a 500 error.
I forgot to mention this yesterday, but I'm using a shared mailbox in M365 and deselect the option
Strict Matching. According to this thread, this should work for both remote inbox & outgoing mails.
For me it's only working for inbox and only after some trial & error: upon first submitting the OAuth2 authentication (for remote inbox) it reported an error
Email Mismatch: Expecting Authorization for firstname.lastname@example.org not email@example.com eventhough I had deselected the
strict matching option. After some retries It did work.
When I configure OAuth2 separately for outgoing mails, I also receive this mismatch error, even after several retries.
It seems to me this option for
strict matching is not 100% bullit proof