IL-2 account and Steam

[Oistrakh]

Hello, I bought IL-2 Sturmovik: Battle of Stalingrad on steam, the game runs once and after exiting and re-entering it does not load the missions, as if I did not have an account. To use it again I go from steam to game properties, local files, verify file integrity, there it tells me that you have to re-download 1 file. After that the game works, again I have to log in and link the Steam account to the IL-2 account and it works fine, but only once.
I hope you can help me. Thank you very much!