@M66B: I got my domain email transferred to Microsoft 365 just fine, I just choose Microsoft oauth in the account setup menu, to add it alongside Gmail. It looks like it uses the same username/password as before, independent of my main Microsoft account.
I'm wondering if you can explain this screenshot, though.
It shows a contacts folder with a bunch of random letters/#s as before. I had emailed some people but never saved them as contacts in my webmail.
There is a 2nd screenshot, but I won't upload it, due to it containing my full email address. Inside this folder were several messages.
All of them had the header:
Microsoft Exchange Server
Retrieval using the imap4 protocol failed for the following message: <insert random # here>
In the message body it says basically the same thing, but states that it hasn't been deleted, and that I might be able to view it through their webmail interface.
I've tried deleting this folder after moving the messages to the inbox. Your app acts as if the folder was deleted, but it reappears after refreshing.
Ideally I'd like to be able to view all messages from all my accounts from within your app. That was the main reason I bought the pro features. All other folders in this account and their contents appear to be fine.