Update: it was an issue with API keys due to a previous install.
Update 2: new problem, qBittorrent has an I/O issue, probably involving the final destination for the media: my Synology NAS. Any advice here is appreciated.
Update 3: I was having issues with mapping my Synology NAS as the root folders, so I restarted the *arrs and now they are unreachable. The solution was to reinstall them without uninstalling them because my computer is weird.
Once a year I try setting up Prowlarr, Sonarr, and Radarr and I felt confident so I reinstalled them. The *arrs are connected to qBittorrent (all tests succeeded) and Prowlarr (again, tests succeeded) and vice versa. I added every indexer that I could successfully connect to (which was most of them) and currently have all of the web UIs open <IP address>:<port> which work as expected. Everything seems to be communicating and functioning as intended so I tested Radarr. I found a popular movie and started monitoring it, this was about 30 minutes ago. It hasn't shown up in qBittorrent and I'm not sure what I'm missing; can someone help me troubleshoot? In other words, how do I know definitively that this movie I have selected will download and when will it download?
The *arrs automatically check for availability every 15 minutes or so. If the movie is monitored, it should have started a download already. Did you check if Prowlarr's indexers also show up in Radarr's indexer tab?
Did you try manually searching for the movie (interactive search)?
When starting an automatic search in Radarr (Search movie), in the bottom left of the sidebar should be a progress indicator. Does it say that releases were found or that a report was sent?
Ok, I'm learning and thank you! Let's start with the first question...the Indexer sections of Radarr and Sonarr have nothing in them (this wasn't mentioned in the tutorial I was following), how do I add Prowlarr to them?
You need to add your *arr apps to Prowlarr. Add them in the tab "Apps" and use "Full Sync" as the sync level. If everything works, Prowlarr should add all indexers to the apps after a short while.