Dropbox sync login loop

Our team recently moved to Dropbox for sync, and setting up colleagues one by one has been successful except for one.

When this user clicks on the Dropbox logo, or the “add Dropbox sync store” from the dropdown button - Safari opens up with the Dropbox log in page as normal. He logs in with the correct details, gets the "Do you want to allow this page to open “DEVONthink 3” message - and clicks “Allow”.

Then he gets another Dropbox login page and the same entire cycle is repeated endlessly.

In the DEVONthink Sync tab the dropdown Sync Store list remains empty.

This user has DEVONthink v 3.8.6 and OS X 12.6

We have tried the obvious - comparing settings with a successful setup, rebooting etc.

One difference is that this user does NOT have his own Dropbox account, so does not have any Dropbox app/software installed on his computer. But maybe this is still needed to enable DEVONthink’s Dropbox API?

The Dropbox application is not required to have a DEVONthink Dropbox sync store.

Have him hold the Option key and choose Help > Report bug to start a support ticket.