So I had this same problem and solved it by opening up an incognito tab in Chrome. I then followed this advice:
"just go to iTunes, sign in with your chosen Apple ID, goto iTunes Store, scroll to the bottom, and click on "Podcasts" under the Explore column. Once there, click on "Submit a podcast" from the right hand menu still inside the iTunes Store, this will use your credentials to logon Single Sign-On through your browser."
So when it pulled up the site, it pulled up the Chrome incognito window instead of my regular window (I think something with the cache was causing the issue) - and when it opened the site in the Chrome incognito window, it wouldn't login with the single sign on and made me enter my credentials again to login. But once I did, it didn't redirect me to itunes connect, but signed me into podcast connect! Problem solved!
I hope this works for you too!
I'm on a MacBook Pro, using latest version of Chrome, just signed up for a new iTunes Store account to manage this podcast about 1 1/2 hours before I successfully logged in.
- David