Alexa "loses" IHeartRadio account? (On both an Echo & a Dot)

[mom2aussies]

I've been using an Echo since August, and just got a Dot for upstairs.  I like to play a radio station on IHeartRadio in the mornings.  Most mornings, this works fine.  But at least once a week, Alexa says she can't find an IHeartRadio account on my profile.  This morning, I was playing the radio station on the Echo downstairs, but got the "can't find an account" message on the Dot upstairs.

Anyone have any ideas what is causing this?

Thanks.