In order for my local server to show up I have to switch from my user account to the guest account. I had been troubleshooting the fact that the server wouldn’t show up in Plexamp and only discovered that it does show up for the guest account after a considerable amount of time and a wide variety of profane utterances.
There appears to be an issue with your server in general. Apparently it has been “seen” by plex.tv last time ~2months ago.
If plex.tv doesn’t know that your server is running, it cannot inform plexamp where to look for the server.
You might want to check if there are issues contacting plex.tv from your server machine.
DNS-based internet filters or “DNS rebinding protection” in your DNS resolver are also worth checking.
I don’t know about this filtering-rebinding stuff, but I changed my router’s DNS setting from automatic to Cloudflare/Google. I also forwarded port 32400 to my server for good measure. One of these things has cleared up the plex.tv connectivity problem. I can now access my server from Plexamp regardless of which user account I use.
I will note that in the support page:
the last paragraph seems to indicate that “all of the above” must be true for there to be problems. I also wonder if the DNS section should be expanded on. I might try un-forwarding the port in order to see if that actually has any bearing on this problem.