The situation seems very confused. Searching on the name of your podcast throws up two podcasts of that title, both authored by you, with feeds at
https://anchor.fm/s/90809a4/podcast/rss
http://feeds.soundcloud.com/users/soundcloud:users:451611129/sounds.rss
Neither is at all up to date or seems to match the feed you link to: this latter works perfectly well in iTunes when subscribing.
Attempting to validate the feed in Podcasts Connect brings up the 'already submitted' error, which is quite normal - once a feed is submitted it can't be validated (unless it's rejected). If you have submitted the feed and got no errors when you did so, then the submission is under process and as I say you can't validate the feed there again.
Is this the situation, that this is a feed you have only just submitted (or tried to submit)? I'm surprised that there are already two versions in the Store - you're not supposed to be able to duplicate titles. It would be advisable to delete them: you may have difficulty with the Anchor feed as it would presumably have been submitted under their Apple ID, not yours, so it would be up to them. The Soundcloud one should be deletable by signing into Podcasts Connect with the ID used to submit it and clicking the 'delete feed' link.
If the error you are getting is not the 'already submitted' one, then what is it?