Nexpose: Stuck at login

I've install NexPose on my Ubuntu 18.04 laptop following these instructions. My 1st time launching NexPose went fine and I was able to launch, login and activate NexPose. However, after the 1st time, I'm now stuck at the login screen every time I try to use NexPose.

What I do every time:

1. In the terminal, run sudo systemctl start nexposeconsole.service
2. In the Firefox browser, go to
3. Wait for it to load
4. Enter my credentials and Press Enter or "LOG ON"
5. NexPose does nothing. Just stuck there.

Is this a problem with Ubuntu, Firefox or NexPose? How should I fix this?

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