UE4+Gamelift client connection fails

Hello!) I have an issue with client/server connection. I created a game session, reserved a player session, got the URL for a client. But when the UE4 client calls ClientTravel("ip+port+?+PlayerSessionId=...), the server's game mode doesn't fire either Login() or PreLogin() functions. Because of that, I can't get a PlayerSessionId from the "Options" argument and validate the PlayerSesssion on the server and Gamelift closes it after 1 minute. When I run a server locally without Gamelift, "Login()" fires as expected. Gamelift health check works great in the server's game mode as well. Please help!