What does that mean (problem solved)?

I just renamed myself to minecraft and suddenly it says:

What can I do?

I solved the problem:

If something like that is with you, you have to log out of the eavesdropper and log in again, then it should work.

That means so much that Minecraft doesn't know you. Should go again soon, they must first realize that you have a new name

Minecraft needs something to sync your name with the game servers. Just wait a few hours. If the problem does not solve then it is best to contact the support.

Close game and launcher, wait 5 minutes and try again

This can happen if you change your name. Just try logging out and then logging back in. Otherwise just wait a bit

Wait a bit, that takes a piece at Minecraft. But you can close your game and launcher. Unsubscribe beforehand. Then start and log in. Try. If it still doesn't work, wait a few hours or until tomorrow. Then log out again and restart the launcher. Then log in again. Then everything should go.