Mail quits immediately after opening

Early this year I had to setup a GoDaddy Outlook account in Apple Mail. That was hours of work to get it going, but it’s worked fine… until we realized the lady who set everything up setup all three emails with Office365 for over $200/year each. We didn’t need that, so my holiday weekend project was deleting and re-adding those emails. I could not just downgrade the accounts that needed to be just email, and I had to wait 24 hours to add them again. But I digress…

I deleted two emails and added them back again, using their original passwords. I figured (hoped) that would allow me to get up and running in Mail again. A couple of Mail exits and restarts, and I got rid of the symbol showing no connection, and could send, so I thought I was up and running. Until I talked to a coworker who wondered why I hadn’t responded to any of her emails yesterday. Whoops! My test “to” email never showed up.

I can log into the web app using the email so I know that’s working well and I see all the emails I never got into Mail.

I decided to setup a new Exchange account in Mail. It seemed to go well, which was a far cry from my attempt in January. I’m waiting for email to start coming in, and decided to restart Mail. BAM! Mail will not start at all anymore. It opens and closes, again and again (yes I’ve rebooted)

This is the error (that I think pertains, the report is much longer) - where can I delete the account from the file system so I can get Mail working again? Or create the folder ID it wants?

Thanks as always,
Early 2015 MBPr, Sierra

Application Specific Information:
EWS store S{MFEWSStore <MFMailbox: 0x7f85ea535ce0> Sent <MFEWSAccount: 0x7f85ea492df0> (1695AA03-F3CC-4FF4-94C6-61BDC6C434B4)} doesn’t have a folder ID
**** Terminating app due to uncaught exception ‘NSInternalInconsistencyException’, reason: ‘EWS store doesn’t have a folder ID’*
abort() called
terminating with uncaught exception of type NSException

It gets more interesting. I went into System Preferences and deleted the new account from the Internet Account section. Now I can open Mail again.

I go back to System Preferences and see my original account has Notes and everything else checked. I uncheck all but Mail. It asks for the password and refuses the one I put in. I click on Details and add the password there, and it takes.

Back in Mail, I see the account, with the new emails that came in yesterday and today.

Then I get a popup saying this Exchange account has been added with a “not Now” or “Turn On” option. Doesn’t matter which I select, the Exchange account eventually disappears from sight.

But at least Mail is opening again!