I have an unlocked 920, bought in Finland, and I'm using it in the US on at&t. I haven't been able to connect to Twitter, tried different apps including the official Twitter app. I have strong signal & Wifi, OS version 8.0.10211.204. iPhone and GS3 connect perfectly using the same SIM card & Wifi. Have tried soft reset already. When I try to log in the official Twitter client displays: Unable to log in. Failed to validate oauth signature and token. Other Twitter apps display a different message, but none of them can connect. Any ideas?