Bad Gateway on CTFd instance

Course: Kibana Security Analyst
Version: Image version: 3.8.1, CTFd version: 3.3.0
Question: I just completed the training videos for the Kibana Security Analyst course but I'm not yet done with the last set of lab exercises. I'm able to access the lab environment URL, but not the CTFd URL. It keeps on giving me a "bad gateway". I've tried pausing and resuming the workspace a few times, and have also restarted the workspace machines but still not having any luck. Could you help me get unblocked, please?

I also tried to follow this suggestion in the terminal for both the lab environment and CTFd, but there is no "server1" so I'm getting a message "Could not resolve hostname server1: Name or service not known" when I try to issue the ssh command.