Unfortunately, this is just a End user help and no one will directly contact to help here beyond the posting and links they give you here. You must log out off all sync devices to setup the sync otherwise you will not be able to change the setup.

https://support.mozilla.org/en-US/products/firefox/backup-recovery-and-sync/sync-data

I sure thank you for the reply! After hours upon hours and a couple days even, searching this problem out, the culprit was finally located. I set a Filter in my email so to stop a certain business sending their email constantly. Their email continued so much, even a few times each and every day, I tried to set their emails as spam, but they kept coming using a different Subject and even address is why the spam didn't work. So I set a Filter to their email and a certain setting inside this Filter caused (all) of my email to actually stop. I couldn't send or receive. It drove me nuts trying to figure just what the heck is going on. Finally, a friend that works at my email provider found that this Filter that I set was the culprit to not receiving or sending of email. Thank God!!! Basically a simple little thing turned out to be humongous though. Anyway, I really appreciate the reply and can't thank you enough for doing so. Am just o trilled to finally find the problem though. Now I got to figure out a way to (again) stop those annoying spamming emails that I tried to stop before because once this culprit was fixed, there was those emails again. Thanks so much!!!

Good to know sometimes it could be simple and sometimes the outcome isn't what you wanted. As anything always make sure your email filter is correctly set so you can filter junk/spam out but not important emails. Glads it's not sync issue as that can get weedy as well.