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What SIP Trunk Statuses Mean

The trunk status shows whether 4phone can actively exchange calls with your telephony provider. Open trunk diagnostics (the flask icon next to the trunk in the list) to inspect its current state.

Registered​

The trunk is registered with your provider and ready to handle calls.

This typically means:

  1. the username and password are valid;
  2. the host and port are configured properly;
  3. the transport protocol matches your provider's requirements.

This is the expected healthy status for trunks that use username/password registration.

Active (IP Auth)​

The trunk is active without SIP registration. Your provider authenticates the connection by IP address.

This is the normal healthy status when your provider uses IP-based authentication rather than SIP registration.

Connecting...​

The platform is currently attempting to connect to the provider or waiting for a response.

If the trunk stays in this state for a long time, check:

  1. whether the provider host is reachable;
  2. whether the port number is accurate;
  3. whether the transport (UDP, TCP, TLS) matches the provider's settings;
  4. whether the provider is blocking connection attempts from your IP.

Disconnected​

The trunk is temporarily inactive. This can result from a failed connection attempt or manual deactivation.

If you did not disable the trunk intentionally, open its settings and click Check again in the diagnostics panel.

Registration Failed​

The provider rejected the registration request because the connection parameters did not match.

Check

This status does not always mean a wrong password. It can also appear when the host or transport is wrong, or when registration is enabled on a trunk where the provider expects IP authentication. Check the hint inside the diagnostics panel for the exact reason.

What to verify:

  1. username and password;
  2. whether registration is required at all—if the provider uses IP authentication, disable registration;
  3. whether the transport protocol (UDP/TCP/TLS) matches;
  4. whether your server IP is allowlisted on the provider's side.

Server Unreachable​

The platform could not complete the trunk status check, usually due to a temporary network or connectivity issue.

Wait a minute and click Check again. If the status persists, contact support.

Provisioning​

Trunk settings are currently being applied. You will typically see this status right after creating or updating a trunk.

Wait a few seconds and run diagnostics again.

Error​

A general error occurred. Specific details are shown in the diagnostics panel hint.

Open diagnostics, read the message, and follow its recommendation. If the cause is still unclear, double-check every trunk parameter from the beginning: host, port, transport, username, password, and registration mode.

How to Isolate Trunk Issues Quickly​

Troubleshooting order
  1. Open trunk diagnostics and read the diagnostic hint.
  2. Confirm that the right authentication mode is selected: registration or IP authentication.
  3. Double-check the host, port, and transport protocol.
  4. Verify the username and password.
  5. If everything matches, confirm with your provider that your IP is allowlisted and their server is reachable.

What to Do After Fixing the Settings​

After updating the trunk parameters, click Check again in diagnostics and place one test outbound call. A healthy status indicator is a good sign, but a live test call confirms end-to-end audio and routing.

For a broader troubleshooting reference, see Common Issues and Quick Fixes.