I've found a way that seems to help.
Mostly I prepare a post in Word, sort out font style & font sizes, formatting like bold and italics and font colours. I then do a copy and paste into the forum post.
It then crashes.
I suspect the embedded Word formatting is too much for the forum to cope with.
So for long posts I prepare them as normal in Word but then copy and paste into MS Notebook which removes all the formatting.
A copy and paste from Notebook to the forum then seems to work OK.
I then have to go though the post to put in bold, italic and font colour formatting which it very tedious. But it seems to work.
Yes, I learned, the hard way, to either do a word doc and copy and paste, or start and email, from which I can copy and paste.
Most annoying to have written a lot and then it disappears, or just won't send.
I had to change my user name and open a newaccount here last year because I was unable to post or reply to anything under my original Rella one.
This one is not without issues but I have learned to cope, and develop patience, which I am always short on.
I cannot see if anything is posted in my signature line area because it dose not show. And to post anything, I have to first preview it, then hit post, then hit preview again and then post.
If I hit post first I get ...
The following error or errors occurred while posting this message:
Your session timed out while posting. Please try to re-submit your message.
And the same when I preview first, then hit post... It is as if it requires a double effort. Maybe to see if you are serious

And often when I have posted something, I go back later and it is gone.
But I am plodding along