Exchange account only works every second time after opening MS Outlook

Hi gurus,

I've had a lot of trouble with an account in MS Outlook.  I'm running six email accounts, all are Exchange based.  Five run perfectly, one is a nightmare.

I've deleted .ost files, rebuilt profiles, pretty much everything I could find through a comprehensive Google search that may have been of assistance.  Sadly, nothing has yielded a result.

I am running Windows 11 on 64 bit PC, Outlook 16 (Version 2312).  I have no other mail apps setup.

Currently, when I open Outlook, the trouble account will give the error message "Cannot expand the folder" when I click on it in the left pane.  If I restart Outlook, it will work perfectly.  If I restart outlook a second time, the error will reappear.  If I restart Outlook a third time, it will work again...  etc.  The problem seems to occur every second instance that Outlook is started, then clears every other.

The only thing "outside the norm" I can think of that may have had an impact, is that I renamed the account display names using MFCMAPI.  This has worked fine for the five other accounts, which were also renamed at the same time.

It is worth noting that at one point, even after several restarts of Outlook and the PC itself, the Email would show in the left hand pane, but would not appear under File > Account Settings.  It is showing again now though - I dont believe I made any changes that would have prompted it to reappear?

Also worth noting is that looking at the profile through MFCMAPI, the trouble account is shown twice.  Once with the original name, once with the new name.  All other operational accounts are only shown once, under their new name.

I have deleted the .ost file several times to allow a rebuild.  Possibly worth noting all other accounts that are working have multiple .ost files for the same account (three each), however the trouble account only has one .ost file associated with it.

One other email out of the six shares the same domain as the trouble email.  It is working fine.

I'm at an absolute loss, and have no idea where to turn for trouble shooting from here.

Any advice would be greatly appreciated!