I am currently playing Minecraft on the Switch version, and have been playing multiplayer on my friend's realm since January. We were able to connect and play without any issues, but two days ago, the game suddenly became slow, so I restarted the software. After that, I was unable to log in to my friend's realm.
I cannot log in to my friend's multiplayer server with smartphone.
Another friend is also playing on Switch and has no connection issues.
I have tried restarting the software, reinstalling it, and resetting my home network devices (Wi-Fi), but I cannot move past the "generating world" screen when logging in to realms.
I can log in to my own realm server without any problems.
I also tried a wired connection, but it failed as well.
When I tried to log in using public Wi-Fi, I was able to log in to my own realm server, but still couldn't log in to my friend's server.

The game freezes on the "generating world" screen.