when using steam, Client lost connect after ServerTravel

I built a dedicated server and a client for my game project. Reference shooter game, I managed to create an internetsession for my dedicated server and the client connect to it successfully with steam. My game has several game modes to iterate over. What I did is to call updateSession to update gamemode of the internetsession: if update succeeds, in the call back function to call serverTravel. But the client lost connection, after change to the new gamemode. Does anyone know how to successfully travel Client, when using steam? Already did a search on the forum, didn’t found any solution. I would really appreciate it if anyone can give me an answer to this question.