I cannot get my log-in to facebook to work since you sent Tty Firefox VPN and I don't use mobile apps

I cannot get my facebook account to log-in. I get sent a Facebook code, type that in, then get a character code and type that in and get sent round and round in this cycle. I have tried syncing, and they suggest there may be a loop or similar in my browser that is preventing it, and I don't know where to find and try to fix that, if it is.