Ruben & Gizmo --
You're still over my head - "speaking Greek" as it were. (But that's nothing new, to me.)
I do NOT get so far as posting (SUBMITting) my entry. The message appears when I click on PREVIEW POST button, in what would normally be the Preview area. I'm just wanting to review my keyed text for proper syntax, English, grammar, etc.
So I click on PREVIEW POST and immediately I get the FORBIDDEN error message shown in my earlier post.
I see several other threads on this message board related to the FORBIDDEN message. None of the others APPEAR to be related to what I'm doing, but I could be out in Left Field when I say that.
FWIW, any of my attempts to edit my older posts - which contain MORE THAN three URL links to what are still live / viable entries, either in or outside the UBB message board (or both) - will also generate the FORBIDDEN message. Thus, while those older posts (all entered by me via an earlier UBB version) were accepted / processed by / functional in that older UBB release, they will still function in 7.5.7 without error messages (links are all viable and active). BUT: any effort to edit that old post and then PREVIEW said post will instantly kick up the FORBIDDEN message. (FWIW - I entered / submitted the content of that old post.)
Are you still maintaining what you've stated, just above this post? (FWIW, I am not able to check the server for presence a Mod_Security component, as I write this.)
Just for kicks, I'm going to open another post below this one, and add a number of URLs to it to see if I get that same FORBIDDEN error message here.
RIck-
8^D