Coincidentally, this is a case where there actually was a bad configuration somewhere in SmartThings. So as discussed in this topic, on the live dashboard the 3rd time you visited the dashboard it logged you out automatically. On staging it showed a blank screen except for the navigation where you were able to log out yourself.
Normally we would expect the issue to be either an outdated token or similar in the browser dashboard data where logging out will resolve the issue, but in your case there must have been something wrong on the ST side.
I’m glad that it is working for you today.