Your problem is your CDN, Stackpath: I’d guess it’s rejecting the feed validator request based on User-Agent string. If you use curl to request the feed, then it serves back Content-Type: text/html and
Stackpath
Sorry, you have been blocked.
This website is using a security service to protect itself from online attacks. You performed an action that triggered the service and blocked your request.
There’s a reference number for the block too, but you likely won’t be able to get the reference number that the validator is seeing.
If you pretend to be Chrome, e.g.
curl --header "User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.113 Safari/537.36" https://www.rnbjunk.com/feed/
then you get the RSS feed not the error.
So I think you have to fix your StackPath configuration to be more lenient about the User-Agents for your feed URLs. There’s an article here that says News uses User-Agent: Googlebot-News and at first glance StackPath is blocking that too.