Thank you for the quick reply. The sim is fully running, I am connected to the Internet, I have the English (US) language pack installed and active. I have an active and working microphone. I set the callsigns to default and restarted the computer. Unfortunately, nothing helped. FSUIPC works for sure because other programs such as MobiFlight Connector work with it. I would like to add that everything was working well until yesterday. Only after updating to version 2.6.3 it started to disconnect.