When a key does not take

Work down this list before assuming the key is bad.

1. Read the card's status line. Kustos checks on save and says what happened. "Unauthorized" is a wrong key; a timeout is a wrong address.
2. Check the address in a browser tab. If you cannot reach the service by pasting the same address into your own browser, Kustos cannot either.
3. Watch for localhost across a container boundary. If Kustos is in Docker and the service is not, localhost means two different machines. Use the host's address on the network instead.
4. Copy the key again. A trailing space or a half-selected value fails in a way that reads exactly like a wrong key.
5. Confirm the API is switched on. Tautulli in particular has its own enable toggle, and the key is visible whether or not the API is running. This only applies to a Tautulli you installed yourself — one Kustos set up switches the API on for you.
6. Check you signed in to Plex as the server owner. A shared account reads fine and writes nothing.