The problem still persists. No error messages however.
So when I hit Send the post just loads and loads, the reply window never disappears now.
The post is made, if I reload the page, or the board page it's there. So the posting happens.
I tried to look into he dev console, and I see some errors, but the page then says "paused on debugger statement" so I can't see what happens when I hit send (for I can't hit send).