You are playing on a phone or tablet? There's not many things to try with that. Do you have the FB app too? If you do, it has to be signed in to the same account you use for T11. Also you could try deleting any saved data (you will have to type in your log in again).
And make sure your connection is strong, I might restart my router if using wifi.

You also could try sending a request to Nordeus Support and they may have better idea of how to fix.