WOW! I THINK I HAVE FOUND THE CULPRIT! AND FIXED IT.
In DNN 7.3.3, (THIS MAY ALSO APPLY TO OTHER VERSIONS) If you have a dnn site where SSL is required and the under ADMIN >Advanced settings and you have the entire site is set to FORCE SSL, You have to make DOUBLE SURE that any new page you create has the FORCE SSL Check box selected WHILE YOU ARE IN THE PAGE CREATION MODE from the DNN Control panel.
Failure to do this in DNN on an SSL Forced site will result in a PAGE NOT FOUND ERROR and your PAGE NOT VISIBLE. Althuogh you will get a blank page and or see it show up in the menu. However when you click on it, you will get a PAGE NOT FOUND ERROR. Leaving you with the perception that your page WAS NOT CREATED. It appears that if SSL is required, Adding a new page does not automatically set the SSL Check box by default
Tryit and you'll see this may reproduce the issue.
1) Create a self-signed test certificate.
2) (In my case) Force the entire DNN Site that was upgraded from DNN 6.2.9 to DNN 7.3.3 behind SSL
3) Now try adding a basic page through the DNN Control Pane.
In my case adding the page via the DNN Control panel did NOT automatically set the "IS SECURE PAGE" however adding a page via the PAGE MANAGEMENT feature CORRECTLY CREATED A SSL "IS SECURE PAGE" automatically without my having to physically select the is Secure Check Box.
The Solution?
Basically, If you ADD A PAGE through the DNN Control Panel, Make sure that you Select the IS SECURE Check Box under ADVANCED SETTINGS>Other Settings WHILE IN THE CREATION MODE. Then your page will be created and visible.
If this is an overlooked Feature that I just never encountered then consider its a lesson learned. However, if this is a BUG where adding a page from the control panel behind a FORCED SSL Site, then hopefully as far as bugs go maybe it will get fixed.
Either way, I wanted to share my findings with the forum. Again if this has been a known issue with DNN or I over looked a hidden "Feature" my bad... but I really do thank everyone in the forum for their suggestions and will take note of them.
Hopefully, if someone else comes across a similar issue of SSL site that was upgraded and could not add new pages from the DNN Control panel, this post will help them.
Cheers everyone. And Thanks!
Wow, Ya just gotta love those SSL "GOTCHAS!"