When trying to apply skins through the minecraft launcher or the minecraft website, both don’t want to properly load the skin library up, same goes for trying to apply skins through client mods like essentials, requests to minecraft to apply skins fail constantly, and give errors saying there were connection issues or that issues occurred, however it isn’t a problem with my own wifi or internet as I checked and everything is working at full speed with no issues on that end, something is definitely wrong with minecraft itself.
Note: I am not sure about the affects version as I don’t know what that is and can’t seem to find an explanation online, it is simply the latest version of the Minecraft Launcher for Minecraft Java Edition 1.21.11 on Windows 10/11
I had a similar issue where I could not connect to any minecraft-related server including dungeons. It turns out it was an issue with the ‘intel killer performance suite’. I went into task manager and force ended any tasks with ‘killer' in the name and it immediately connected again. I then went and uninstalled anything related to it in apps and programs. Check if you have the same useless software on your PC and try closing it / uninstalling it.