Enable CORS for VAST playback

I am attempting to enable CORS for my site to be able to run VAST ads on my video and I keep getting the following error:

Access to XMLHttpRequest at ‘[vast-adserver-domain-link]’ from origin ‘https://www.indtheater.com’ has been blocked by CORS policy: Response to preflight request doesn’t pass access control check: Redirect is not allowed for a preflight request.

I am attempting to run VAST ads hosted by adsterra.com and it does not seem to work with a certain player. Here is a link that shows there error in the video player:
https://www.indtheater.com/test
The player I am using is: Ultimate Video Player by FWDesign | CodeCanyon

Below the main player, I have two text ads to see if those work, then I am running the VAST ad through the fluid player and it seems to work, but doesn’t play the HLS/DASH files hence the main player. All my video files are hosted on Cloudflare Stream.

I have followed the suggestions on enabling CORS, updated the .htaccess file, purged cache, purged individual files, etc. No success.

Attempting to figure out if this is something that can fixed on Cloudflare or if it needs to be addressed on my host/server-side. I also was attempting to looks at setting access rules with Cloudflare for Teams…but a little lost there and not sure if it is even the right way to do things.