I find as long as you are typing no more than 3 lines of text (assuming your using 1080p display with browser full screen) and you click on the "post reply" button instead of "reply". Most posts should be successful even after showing the error. I would suggest once you have got your post typed, copy the text just in case the post fails. Then paste but delete a few words and try once more. It is possible to edit the post to include more information

Worth noting that just because you get the error message, it doesn't mean the post did not go through. Always update the webpage and check the latest posts afterwards, to find out if it worked or not.

It’s been like this for several months.

The following error occurred...Sorry the application encountered an unexpected error. Information about this error has been logged. If you continue to receive this message please contact the board administrator.

This has been happening for a long time now. I never know if my post is accepted or it has never happened