Did a new, first-time install following the instructions for Docker. It all appears to work correctly. I am able to access the interface. When I reach the instruction to enter the default credentials (admin/birdcage), I get a popup error message:
{hostname}:7008 says
An error occured while logging in
[OK]
If it matters it's a Debian install, otherwise functional and running Frigate_nvr and a couple of hang-off applications.
Did I miss something obvious?