MacOS: High Sierra 10.13.6
After a random amount of time the iCloud tabs button on MacOS Safari becomes disabled, making impossible to rich the iCloud tabs of other devices.
Of course syncing is enabled in System Settings > iCloud > Safari.
I have been able to workaround the problem rebooting MacOS or logging out and logging in the user, which both solved the problem temporarily until the next random block.
Any advice on how to fix it or how to solve it without terminating the user session?