I restarted HA (actually installed the latest update) and the connection was restored.
Obviously, I couldn’t have fixed this remotely through NC. And I have no clue what was wrong. So I’m hoping this remote access becomes more robust in the future.
I’ve noticed recently (in the last few weeks?) that my remote connection has been getting turned off occasionally even though the connection should be retained thru restarts, etc.
I’ve had to go in and turn the toggle back on manually several times.