Ok so I think it was the language setting on my own Lemmy instance. I set it to only English but that was giving the error when trying to post over here to lemmy.world.
I reset it to all languages and the error went away.
I made an account on an instance other than lemmy.world and my user experience has been greatly improved. It was after getting this error that I finally decided to do it. I was having major issues with loading, voting, and commenting prior to making the new account. I think that lemmy.world must be overwhelmed with users right now.
same here. saw this error at first and then just a generic "error trying to post, try again". could not get it to work... posting via my instance's webui worked, but only after selecting a post language. is that something communities/instances can enforce?