Friend on mac can't connect because of strange error

Me and my friends all over the world are trying to connect, and the only friend that can't connect has mac and it has this error:

Internal Exception: io.netty.handler.codec.DecoderException:java.lang.IndexOutOfBoundsException: Index:25, Size: 5

We are playing with T-launchers. Its okay with Windows.

Quote from Roman

That issue typically appears if the chosen in-game name is invalid and does not comply with Mojang's username restrictions: https://help.minecraft.net/hc/…36712-Minecraft-Usernames

No, it didn't helped

Quote from Roman

What is the Ingame name?

Take a screenshot.

I solved the problem! My friend had different nicknames at launcher and his profile in Tlauncher.org

Thank you a lot!!!