I have seen this problem has been asked about before. However not a single solution provided has worked for me. I have no restricted data or a battery app that's affected my syncing capabilities (or any program like that for that matter). I have tried the sync now button, I've hidden the synced tabs menu and dropped it back down, I've pulled down the synced tabs menu, I've started a new Firefox instance after completely shutting it down, as well as everything else that was suggested. I've used a search engine looking for a solution and have come up with nothing. I'm running Firefox on my laptop, Android phone, as well as my Android tablet. I'm using my laptop with opened tabs. The first time I synced Firefox it worked. Every time since then (I've tried like 100 times and that's not an exaggeration) it hasn't worked on either my phone or tablet. Could someone please help because I'm at my wits end and am considering going back to Chrome. For anyone who can help I sincerely thank you for your time and effort.