Big thanks for noting and reporting this - I'm fairly early in my unraid / docker / conbee journey and I couldn't understand why the web-ui was only giving me a blank page. I had briefly tested the conbee on a raspberry pi before tackling establishing a container on my system for it. Appending the URL with "/login2.html#OVERVIEW" allowed me to get in and get configuring.
And big thanks to @thecode for creating and supporting this - I thought this would be more of a headache to get working than it has ultimately ended up being!