Updated LR CC not able to connect to server

Hi

I'm on iMac, fully updated (Catalina 10.15.7) using updated Lightroom CC (ver 3.4). 

Everything has worked for years, but not suddenly "Unable to connect to server" ie I cant upload, sync etc.  No changes to wifi, firewalls etc. 

I can access via mobile app on iPhone and Ipad (on same wifi network) and via browser on same computer/network.

I have tried to restart etc but still continues. Sometimes it has connection for a short time, like 2-3 min, then again "Unable to connect to server". 

What to do ??  Its super frustrating...

Appreciate any help and advise.