After upgrading the game from UE4.27.2 to UE5.4.4 we are experiencing crossplay issues between Steam and Epic that causes clients to disconnect and go back to main menu. We have been running fine for a year in our Alpha with crossplay function fine in 4.27.2 but had to upgrade to use new plugins that only had UE5 support. After the conversion, everything seems to work except for crossplay. We are using the latest EOS and Steamworks SDKs for 5.4.4.
Here are the cases:
UE4.27.2: We can Crossplay between Steam and Epic builds no issue.
UE5.4.4: We can play Steam to Steam, or Epic to Epic, but any combination of Steam and Epic causes the clients that are not from the same platform as the Host to disconnect and go back to main menu.
We already diffed our code between 4.27.2 and 5.4.4 and there is no difference in source or project settings relating to EOS or Steamworks SDK.
It feels like something in UE5 or the UE5.4.4 version of EOS is causing crossplay to not function anymore. We have seen mention to use Seamless Travel, but that didn’t seem to help.
Any other suggestions on what may have changed in UE5 would be a big help because everything is running great except for crossplay, and it’s an important piece of the game.
Thanks,
Kyle