Softphone errors
What SIP error codes 401, 403, 404, 407 and 488 mean on a softphone or desk phone, and how to fix them.
Softphones and SIP phones show a number when something goes wrong. Find the code below. Most problems come from a SIP detail typed wrongly.
To check the details, open Devices at the top of the PBX tab, select the device and compare its SIP credentials (Domain, Username and Password) with your app.
401 Unauthorized
Section titled “401 Unauthorized”Cause: the username or password is wrong.
Fix: copy the Username and Password again from the device’s SIP credentials. If you changed the password with Generate a new password, apply the configuration and update the app. It can take up to 5 minutes to connect with new credentials.
403 Forbidden
Section titled “403 Forbidden”Likely causes:
- The username or password is wrong.
- The device may be temporarily blocked after registering with a wrong password. The block lifts after 5 minutes.
- In Bria on a phone, Registration Mode is set to Single Device Takeover.
Fix: correct the details and wait 5 minutes before trying again. While the device is offline or blocked, its settings in Devices show Check IP address for blocking: enter your public IP address and click Check to see whether it’s blocked. For Bria, see Bria Solo.
404 Not Found
Section titled “404 Not Found”Cause: the number you dialled doesn’t exist or was dialled in the wrong format.
Fix: check the number, and try calling it from another phone. See Cannot make outbound calls.
407 Proxy Authentication Required
Section titled “407 Proxy Authentication Required”Cause: the username or password is wrong.
Fix: same as 401: copy the SIP credentials again.
488 Not Acceptable Here
Section titled “488 Not Acceptable Here”Cause: the phone is connected, but its audio codecs don’t match the PBX.
Fix: in your app’s codec settings, enable only codecs the PBX supports: Opus, G.722, G.711 a-law and G.711 u-law. Remove G.729. The device’s settings in Devices list its codecs under Supported audio codecs.
The device stays offline with no error
Section titled “The device stays offline with no error”- Check the Domain includes the colon and port.
- Set the transport to the Transport protocol shown in the device’s SIP details (TCP, or TLS if TLS encryption is on).
- Make sure the SIP device isn’t also signed in on another app or phone.
- Check that your network allows SIP traffic and that SIP ALG is off on your router. See Network requirements.
When to contact support
Section titled “When to contact support”If the error continues after these checks, raise a support ticket. Include the error code, the app and version, the SIP device’s name, and the time you last tried. Never send your SIP password.