I am having the same problem on my iPhone 11. Every time I open Pandora, it looks like my channel is going to open then freezes. When I toggle back to my channels list, there is a banner at the bottom saying that Pandora is buffering...but the buffering process never ends. Have tried a had restart for Pandora several times. The first time it seemed to knock it loose...but it didn't last. All other attempts at the same fix have not even got me that far.
