I got this odd error again when making a post with an uploaded image.
I went to Advanced, uploaded image, placed it inline & posted & instead of returning to the thread I got the error page shown. The post posted successfully though.
I posted about this months ago but I have not seen it since until today. Still an issue. Always happens in the same scenario.
It's rare, but this can happen if you try to make a post at the exact moment the website is spinning up or down a server. Most of the time your post will still successfully go through even though you're shown an error message. If you happen to get this error message repeatedly, please let us know as that would indicate it's a different and bigger problem.
