The Apple Mail app has been misbehaving for me quite a bit (even back on ios12).
When I send an email, it always goes to my Outbox. I need to go to the outbox and send it again- sometimes 3-4 times before it actually deletes from the Outbox.
The more problematic issue on iOS13 is- that I use that mail app for both Gmail and my Work email.
When I send an email and “try to use” my work email address, I select the work email address, and click send, but the Mail app won’t send the mail with my work email address. It defaults to my personal address.
Most of the time, I see “Rejected by mail server”, even though some emails go through (but with my personal address).
Has anyone else had issues with the iOS Mail app and a corporate Outlook server?