I've had a firefox sync account functioning this past year on my Android handset without incident. Today, I need to access the synced info elsewhere. I confirmed FF was auto synced up. It was. I manually synced as well for good measure and it updated to "last synced 1 minute ago." I attempted to login with the same account/credentials on another handset and also a PC and get "incorrect password." Okay. No problem, that's always possible. So I go to use the "forgot my password" "send me a reset link" option. No password reset email delivers. Not to spam etc. The credentials used for FF sync (as can be seen in the sync menu) is username+xxx@gmail.com. I have a sneaking suspicion FF Sync, has a flaw that allows folks to operate accounts with the username+xxx@gmail.com modifier yet the FF sync email system is flawed in not properly handling such emails. Maybe it's something else, yet that's the only unique thing I have to go off of at the moment. I'd greatly appreciate it if someone from the Mozilla team can provide some insight. Thanks again.