I have the same problem but with google play. Everything worked fine until i switched from 4.18 to 4.20, but now since the UniqeNetId type is GOOGLEPLAY and OnlineSubsystemNull checks if it’s equal to FName(“NULL”) it fails. The crashing assertion didn’t exist in 4.18, since they introduced different FUniqueNetId types. In 4.18 RegisterPlayer made an instance of FUniqueNetIdString, whereas in 4.20 onlinesubsystemnull makes an instance of FUniqueNetIdNull.