Cannot create character - Abnormal disconnect - Steam account issue

Hello Grinding Gear Games support,
I am having a serious issue with Path of Exile 2 on Steam.
Problem description:
- I launch the game through Steam
- I successfully connect to the server (Moscow/Milan, ping 70-100ms)
- I get to the character selection screen
- After 30-60 seconds, I get disconnected with the error: "Abnormal disconnect: Произошло неожиданное отключение от сервера"
- I never get a chance to create a character
What I have already tried:
- Restarting Steam and launching as administrator
- Verifying game files integrity
- Clearing game cache (%APPDATA%\Path of Exile 2)
- Resetting network settings (ipconfig /flushdns, netsh winsock reset)
- Turning VPN on/off
My suspicion:
The issue seems related to Steam authentication. The server seems to treat my session as "guest" and disconnects me after a timeout.
My account info:
- Steam login: Steam ID: 76561198102486483
- Path of Exile account: di58#5029
- Game is installed on: D:/SteamLibrary/steamapps/common/Path of Exile 2