Yes, I'll share what I found worked for me
I am fairly certain this issue is caused by already being logged into Facebook in the game's built-in browser. I haven't found a reliable way to log out that since it just gives you a public error page and you can't manage your account at all. I don't know which browser it is or is based on. Maybe Safari or Chrome, depending on device? Maybe logging out in your Facebook app or Safari/Chrome window would work. I'm guessing uninstalling and reinstalling the app might have a chance of fixing the issue also since you'd assume it would break your session in the built-in browser, but if that doesn't work, or you don't want to reinstall, this is what worked for me:
- Log out of Facebook in Safari/Chrome
- Go in-game and tap "Connect" next to the Facebook option, whether for Lost Account or just linking a particular account.
- If you get the error message again, tap the "Safari" icon in the bottom right corner. I assume it's something else on an Android device, such as Chrome.
- If you get the error message yet again, tap and hold the "Reload" icon in the top right corner until a context menu comes up saying "Request Desktop Site", and select that option.
- Now, when I did this, I got an error message but it did log me in, and my accounts that were linked to my Facebook account showed up. You may have to log in, or refresh or something but try a few things to see if it works.