@Vivaldi @fredallas
It would be even better if in each browser (desktop/mobile) in the sync section of the settings a detailed message about the cause of the error would be given.

At least at the level: "this is not your local error, this is an error of our servers. Don't worry, we are fixing them. You don't have to do anything - just wait for us to do it."

Because a lot of people panic and start reinstalling their browser, trying to reset their data - and all need is accurate information about where it broke and what need to do. You can even draw a funny picture from the Don't panic! :) Don't worry, don't panic.