Unable to Edit Template, White Screen on Save

[Bestrafung]

I have never encountered this issue before so I hope someone more knowledgeable can help. I'm trying to edit the template of a mod I just installed (vbTube) but whenever I try to save the template the frame is blank/white (still have the admin menu frame to the left). I have tried all of the recommendations from https://www.vbulletin.com/docs/html/blank_pages with no luck (also, not sure if this applies since the frontend and all other admin functions are fine). I can edit every other template I've tried but not ytm_watch. Can someone point me in the right direction to fix this?

[TheLastSuperman]

Does your host have some form of security measure in place, securi firewall or similar? Not sure why it would do that unless something security/permission/error(possibly reporting) was coming into play.

As a work-around I suppose you could install this mod:
https://vborg.vbsupport.ru/showthread.php?t=257072

Export the custom templates into a .php file, then edit that file directly (using Notepad++) you will see where the template is within the actual php code . Once you're finished (save then) import the template php file to overwrite the current style with your new changes .