QuoteInternal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.
Not a lot to go on, sadly.
nothing in error logs either...
nothing in the server error log either
It only does it when you... er... reply. If you use Quick reply, it seems OK.
To test it, put something in Quick reply and hit "Preview".
Add something, then hit "Preview", again...
Happened to me in quick reply.
Hmmm... I wonder why that should differ?