The behavior isn't normal - Without the error message itself it's hard to say. You're not seeing any tracker errors or anything like that within Deluge right?

Otherwise shut down Deluge, enable logging, then re-start it. See "Enable Deluge Logging" in https://deluge-torrent.org/troubleshooting

Maybe you want to set the log level to "error" or "warning", if those don't yield anything new then set it to "info" to log whatever error it is.

Also maybe update your post with your OS and Deluge / LibTorrent version.

For what it's worth in the past I've sometimes seen Deluge error on a brand new private tracker torrent, sometimes the private tracker needs a few seconds or a minute to update the tracker and show seeds/etc. - in those random cases Deluge ends up talking to the private tracker before all that & that results in it displaying some error like torrent not found at tracker, I forget exactly what the error was. It's a bit odd since I've never seen rTorrent/ruTorrent have that issue, seemed like a Deluge thing. Been a while since i've dealt with that and can't remember how I fixed it, think it involved having a delay before Deluge attempted to load/start the torrent.

for headless you get either Deluge or Transmission

The paid Seedbox providers usually default to rTorrent/ruTorrent for headless torrenting on their Linux based systems. Deluge/Transmission are the alternative clients in those cases.

Nowadays qBittorrent with webui enabled behaves pretty well on a headless system otherwise qbittorrent-nox is also an option.