Why is Google Backup and Sync not working?
To find the solution to each problem, it is mainly required to identify the cause of why Google Drive does not work / does not sync. Here are the 5 possible reasons why Android backup and sync is not working on your device:
The problem in the network connection
The Google Drive app may be out of date
Corruption in application data
Incompatible third-party apps preventing Drive from taking action
Little storage on device to sync
https://www.not-working.co/google-drive-not-working