Hi, From today, the access to the old Power BI Gateway UI have been removed. We can only access to the new PowerBI Gateway UI And, because of that, we have lost the capability to manage the user...
Microsoft is supposedly fixing this bug second week of November.
What worked for me in the meantime (in Edge & Chrome). . .
Scroll below the blank area and click Add New Rule
Then click the elipses in upper right of Edge/Chrome to open settings > Select More Tools > Developer Tools
This opens up all of the mapped users so I can add the new ones.
Good luck!