For those users who are experiencing the "Error 419 - Page Expired".
That has happened to me but I also realize I kept the reply open too long which is why I got the error to begin with. I should have finished the post and hit submit.
I can manage to click back and retrieve the post I was working on then hit submit.
I didn't bother to post about it since I realized I got preoccupied doing something else in the middle of my post.