I had a similar issue. Both Pandora and Alexa mobile apps showed as linked but the Alexa app and also voice commands to play "on Pandora" commanded me to "enable the skill." I remembered that I once setup my Echo Dot for a kids account. So I realized when I enabled the skill to link the accounts, it was enabled for my "primary adult account." Once I disabled the "kids account" in settings then the link completed for the device and apps. Voice commands and the Alexa app worked as expected. I re-enabled the kids account on the Echo Dot and everything continued working as it should. Give that a try, good luck.
... View more