This is a recurrent bug which has affected a number of people. 'PeculiarFinds' (Error - Page Not Found - Apple Communityposted this possible solution though I don't know how effective it is likely to be:
Download the itunes app
Open itunes app
Mouse over "Account" on the top menu bar
Click on "sign in." If you are already signed in then sign out and click on the "sign in" to sign in again.
It will take you to a login page. Log in.
It will tell you something to the affect that you are a new user and aren't able to use all services yet or something like that
Follow the step by step prompts. It will tell you something about a credit card but you don't have to enter one. Just fill out your name and address and continue through the prompts.
It will tell you that you can now log into all of apple services
Open the podcasts screen in the itunes app
On the menu on the right click on "submit podcast"
It will take you to a login screen. Log in
It will ask you to accept terms of service. Accept it.
It will now take you to the podcast connect and you can submit your podcast.l
If it doesn't work then go into the itunes app, click on "account" again, and select "authorizations-->authorize this computer" and go through that process and then try all of these steps again.
podcasts connect is not sending me to the… - Apple Community
If this fails I would suggest reporting it Podcasts Support. Go to Overview - Podcasts - iTunes Connect Resources and Help and click the 'Contact Us' link at the bottom of the page.
If that fails the next step is to contact Apple Support: Support
Don't present this as a podcasting problem - they don't handle those and will refer you to Podcasts Support (or give you an inaccurate answer judging by some people's experience). Present the problem as being the inability to access Podcasts Support.