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Do you have access to a pc you could try accessing your account on - or can you do it on the phone browser? It's possible it's a facebook issue rather than your device. I'm not totally familiar with Windows, so I'm not sure whether there's an option to clear the app data as there is on Android. If the account works OK outside the app, uninstalling and resinstalling might reset it.
It usually happens when the phone is having issues with the data connection
This could be because of too many background apps running, a week mobile signal or the phone throwing a nutty
General remadies are to close all background apps,
To ensure you have at least 2 or 3 bars of 3G signal (or full 2G) or are connected to wi-fi with a good signal
And if that fails try rebooting the phone
yes i get the same,but if i open the people app [wich is better looking than stock facebook] it will conect ,let me know if you remedy this .