Android notification "Error - Please try again"

Sometimes I receive an Android notification from Hearthstone, in my Notifications pane, saying only “Hearthstone” and “Error - Please try again”. This happens every couple of weeks, I think.

Expected: Explain what exactly I am supposed to try again. I don’t know what this is about.

Screenshot:
https://i.imgur.com/i4VOn23.jpg

Galaxy A50 phone, Android 10