Minecraft server, all Steve after restart?

I created a Minecraft server yesterday evening and there were some minor problems, first with the whitelist (probably because of the Pl LuckPerms) and now with the skins. Everyone is somehow a Steve. That came after a restart and I clapped the pl BetterSleeping on it before that. Does anyone know what that could be exactly? Everything works except for the Skin + (with one person, their / sethome sits down every time they come back on).

All plugins

Sounds like your server won't connect to Mojang's (skin) server.

Check whether you have entered the server.properties

online-mode = true

are standing.

One possible cause would be that the online mode is deactivated. If that's false then change it to true.