Bug Report: Rayo Service SMAPI Feed Frozen Since June 12th (PopMaster Podcast)

You may want to contact Rayo, or the Popmaster podcast themselves. Sonos merely points their system to the feed presented by Rayo. They aren’t responsible for the content that is on the Rayo servers. 

I have the same issue, all stopped at 12 June. Podcasts are available up to date on Rato app so appears to be a blockage with the feed.