icloud for windows keeps asking for account password

I have installed iCloud for windows on my Windows 10 64bit desktop.

It asks for my id's password, and I then get a 2FA message in my iPhone (which works).

I then minimise (or close) iCloud (but it is still in my Notification area).

After (approx) 10-15 minutes, the iCloud window appears again asking for my password again.

I enter password, 2FA, minimise the app.... and this repeats ad nauseam.

I have removed the add-in from outlook, but this still happens.

When I right mouse click on the icloud icon, it says the iCloud drive in initializing, and iPhotos do not seem to have synced at all.

I have temporarily disabled my Firewall, but the same thing happens.

My machines details are visible via my appleid login.

I have uninstalled, rebooted, and re-installed iCloud for windows.No Change.

Can anyone shed any light on what this might be?

Thank you