The RSS Podcast URL is the permanent address for your podcast. It is used by all internet browsers and bots to find and read your web page. Like all addresses, it must be written in the correct way. Because you are allowed to make your own RSS Podcast URL, we need you to make sure the format is followed. 

Lower case alphanumeric URL characters are required. A valid RSS URL allows only lower case letters and numbers (no spaces).  a through z and 0 through 9

Special characters are not allowed in the RSS Podcast URL. These include symbols, spaces, and capital letters.