Did you installed / enabled the EasyDiscuss user plugin? If you do and when someone remove a user, EasyDiscuss user plugin will move all the items associated with the user to the user you've specified in 'Owner for orphaned items'.
But for now, to fix your issue, I guess we need to re-associate the user items manually. Can you pass me your Joomla backend admin access and your ftp account so that we can do this for you?
This issue occurs when the discussion cannot find its author. So, here is a simple way to prevent this is by assigning that post/discussion to a another author. So that post/discussion have a author.
Dear Mod, I think i will go with sam on this one. I have a very active website and i do not wish to overlook everything and go through all those messages again and again to find that single respond or command.
@ Sam! thanks! i will install that plugin. However.. i do not have FTP for security reasons. Could you otherswise tell me what to do?
Do you mean Easydiscuss? I am trying to check on your backend but it seems like you already block our access. If you have installed this plugin, for the future user removed, the article will be assigned to the owner for orphaned items. But for the previous user, you will need to assign this post by yourself.