Why can't I connect my Amazon Tap to my iPhone Pandora account?

Until recently, my Amazon Tap would respond to the command "Alexa, play pandora Beatles."

It no longer does. Says I have to link my iPhone Pandora Account to the Tap again.

When I go to the Tap settings for Pandora it says "App Support Unavailable"

What changed?

Why can't I use my Tap to request one of my Pandora stations?

Why, all of a sudden, is "App support unavailable?"