In my case, I had to use this site (since our server is Ubuntu (Linux)):
https://www.dundas.com/support/learning/documentation/installation/dundas-bi-linux-services
Under Dundas BI scheduler commands I ran the status command and it showed that the scheduler was running! Unreal, since it clearly wasn’t. I then ran the restart command by prefixing the whole thing with sudo (sudo systemctl restart ...) to restart the service, and boom, everything came back online.
Side note: getting the {InstanceName} proved to be a bit challenging. I ran systemctl list-units --type=service to see the names of dundas services running, and it showed me the name, which I wouldn’t have guessed.
Hope this helps anyone else searching for answers to this issue!