Google Account Sync Issue

Hello,

I have a big problem that has been going on for quite some time: I can no longer sync any data from my Google account on my Galaxy Note 4 running the latest generation Android Lollipop, which is very frustrating since I can't retrieve my bookmarks added on my computer via bookmark synchronization, nor can I access the history of recently closed tabs...
When I go to Settings/Accounts/Google/, it states that synchronization is disabled, and then when I click on sync for "contacts," an error message appears "Sync Issue. It will be operational again soon."...

I have done a lot of research online and came across this site "https://www.phonandroid.com/forum/threads/astuce-probleme-de-synchronisation-elle-sera-de-nouveau-operationnelle-bientot.40981/" which provided some tips, but unfortunately none of them worked, for example, the very first one involving tapping on an error message that only sometimes appears on my smartphone doesn't change anything...

Do you have any other solutions to suggest besides factory reset?
Thank you in advance because it would greatly help me... ^^'