Are you trying to redirect your show from "Spotify for Podcasters" (formerly Anchor) to your RSS.com account? Follow the directions below (You cannot set up a redirect through the Spotify for Podcasters mobile app).
1. Go to your "Spotify for Podcasters" account on the web.
2. Click "Update Settings" from the top right drop down menu.
3. Scroll down and click the "Redirect your podcast" option.
4. Add your new podcast feed URL and click the button "Redirect."
That's it! Now your listeners and podcast directories will be automatically redirected to your podcast's home at RSS.com