I am also having this issue as of yesterday on the Nintendo Switch on version 1.16.210. Previously, I was just unable to access the store, nothing would load. But now there is an error number attached to it with the same window attached by the original reporter.
I have attempted going into settings, checking for corrupt data, and redownloading the game, but that did not work.
Signing out of my Microsoft account on the switch and back in seemed to have solved this for me.