Cannot log in: "Make sure your device has a working Internet connection and restart VRChat" and "Logging in as SlyFirefly"

Playing on desktop, on merged Steam + VRChat account (Steam first, VRC acc created and connected later).

Yesterday (21.09.24) VRC lost connection to the Internet. The game seemed to work fine before that day but I do have connection problems in general, so it didn’t seem like much.

However, now every time I launch VRC it starts with a home world loading screen, after that for a split second it shows “Make sure your device has a working Internet connection and restart VRChat” and then it immediately changes to “Logging in as SlyFirefly”. After a moment it goes back to the loading screen and the cycle begins anew until the game is closed.

Sometimes the game starts with a log in screen: if I log in via VRChat account the above-described cycle starts, if I log in via Steam it just stops on eternal “Logging in as SlyFirefly” and nothing happens afterwards.

I used my regular home Wi-Fi as always. I don’t run any VPNs on the background and I don’t use any mods or cheats (in May I tried to install Creator Companion but never actually learnt it). I deleted and reinstalled VRChat in Steam but it didn’t help. Some people recommended cleaning VRChat’s cache but after deleting about 19 GB from the folder “Cache-WindowsPlayer” nothing really changed.

UPD: Now it also sometimes shows “Failed to authenticate with realtime servers”.
UPD 2: The issue is (seemingly) fixed by… setting your avatar to default through VRChat’s website. The weirdest junk I’ve ever seen. Still would like to report because it’s strange and I wonder why it happened.
If it helps, the last avatar I changed into was Yugo by Marino from the list of fallback avatars, this was also when I made this one my new fallback.