I don't have another device yo add!
Additional System Details
- User Agent: Mozilla/5.0 (Android 6.0.1; Mobile; rv:67.0) Gecko/67.0 Firefox/67.0
Please explain the problem in detail. What happens? What are the exact error message(s) ?
Sync is optional and you do not need to use it. Sync isn't meant to be used as a backup.