Troubleshooting

Start with collied doctor on the machine. Each line is ok, warn or fail, with the name of the check. Then find your symptom below.

collied doctor

The machine shows offline

The phone could not reach the machine over the tailnet.

Check that the machine is awake and collied runs: the daemon line in collied doctor, or collied status.
If you ran collied stop, run collied start.
A warn on the tailnet line saying "no node state (not logged in)", or a fail on the daemon line whose node is not Running, means the node is logged out: run collied login. A fail on the tag line means the node lost its tag; collied login prints what to fix. A fail on the tailnet line is a problem with the node state folder itself, such as its permissions.
A warn on the reach line means no device of yours can reach the node: check the tailnet policy and that the phone is signed in to Tailscale in the app.
Pull to refresh on the Agents tab to retry at once.

Connection errors are shown in full in the Machines tab, with a button to copy them.

The app and collied speak different protocol versions. Update the side named in the message: see Version mismatch.

Look at the apns line in collied doctor. If it is not configured, follow Push notifications. On macOS, a key the daemon cannot read usually means collied was rebuilt without just collied-install: reinstall it.
Run collied apns test. It reports whether Apple accepted the push; then check the phone.
Check that notifications are allowed for Collie in the iPhone's Settings.
Done alerts only come for turns of 30 seconds or more, never for an agent that is on screen, and not at all when Settings > Notifications > Notify when an agent finishes is off.

The agent has no session ID: Chat says so and retries when one arrives. For Codex, install herdr's hook with herdr integration install codex, and again after each herdr update. The codex hook line in collied doctor warns when it is missing or older.
The session was started before the hook: for Codex, finish the turn and relaunch it in the same pane with codex --no-daemon resume <session-id>.
collied is older than the app: update collied to enable Chat.
The transcript is missing: Chat shows the history as unavailable, with a button to open Terminal.

herdr reads Codex's status from its screen. If a Codex agent stays unknown, or finished turns send no done alert:

Make sure herdr is the version collied is tested against (see Requirements) and install its Codex hook again: herdr integration install codex.
Check the agent's status in collied status while it works. A turn that ends in unknown sends no done alert.
Codex tasks started from collie use --no-daemon. Relaunch older shared-daemon sessions as described in Codex.

The window closed: a pairing window lasts 120 seconds and the first attempt closes it, right or wrong. Run collied pair again.
No answer on the machine: without a y within 60 seconds, the answer is no.
Another user: collied only accepts the owner (owner_user_id, or the user of the first confirmed phone). Sign in to Tailscale in the app with the owner's account.
A tagged or shared-in phone: the phone's node must be untagged and belong to your tailnet. Do not sign the app in with a tagged auth key.
The policy blocks the port: check the reach line and the tailnet policy.

Open an issue: see Support.