i'm trying to connect but, token can not be null or empty, what is that?

It means you don't have a session token... Try closing all of Minecraft including the launcher then loading it back up. May fix it

@_Haxington_ Do you have a strong internet connection?

That wouldn't matter... 'Token' is referring to the session token.

@_Haxington_ Personally, I have never encountered it but a new session token is generated on the pressing the play button on the launcher which is why I suggested that.