Outlook can no longer access In-Place Archive once UPN changes.

We have an org with both 2010 and 2016 exchange all on premises.  The 2016 servers are in Europe and we originally had them using "xxx@company.eu" as UPN and primary SMTP.

The business has asked us to change everyone to a "XXX@Company.COM"  UPN and Primary SMTP.

We have users in the .eu that have been using in-place archives with no issue.  Once their UPN and Primary SMTP has changed they now cannot access the in-place archive.

They (the .eu users) are on a separate network (acquired company in process of getting onto our network) and use Outlook Anywhere.

There is a mix of Outlook Office Pro 2010 and 2016.  
We have recreated profiles and still not working,

The 2010 Outlook clients can see the archive but it says it cannot connect if clicked on.
The 2016 Outlook clients - the archive never shows up.

All of then can get to the archive via OWA with no issues, and I can add a profile from on our network with no issues and see the archive no problem.

Is this an autodiscover issue ??  What am I missing?

Thanks in advance!