SIP 182 Queued vs 404 Not Found
SIP 182 (Queued) is a 1xx Provisional response, while 404 (Not Found) is a 4xx Client Failure response. 182 indicates that the called party is temporarily unavailable but the server has decided to queue the call rather than reject it. The call will be attempted when the callee becomes available. In contrast, 404 means that the user specified in the Request-URI does not exist at the domain. The server has authoritative information that the user does not exist.
Description
The called party is temporarily unavailable but the server has decided to queue the call rather than reject it. The call will be attempted when the callee becomes available.
When You See It
In call center or queuing scenarios where the callee is busy but the system holds the call in a queue.
How to Fix
Wait for the call to be dequeued. If queuing is not desired, configure the server to reject calls instead of queuing them.
Description
The user specified in the Request-URI does not exist at the domain. The server has authoritative information that the user does not exist.
When You See It
When calling a number or SIP address that does not exist on the server. Different from 480 (user exists but is temporarily unavailable).
How to Fix
Verify the SIP URI or phone number. Check if the user is registered on the correct domain. Ensure the domain is correct.
Key Differences
182 is a 1xx Provisional response, while 404 is a 4xx Client Failure response.
SIP 182: The called party is temporarily unavailable but the server has decided to queue the call rather than reject it. The call will be attempted when the callee becomes available.
SIP 404: The user specified in the Request-URI does not exist at the domain. The server has authoritative information that the user does not exist.
You encounter 182 when in call center or queuing scenarios where the callee is busy but the system holds the call in a queue.
You encounter 404 when when calling a number or SIP address that does not exist on the server. Different from 480 (user exists but is temporarily unavailable).
When to Use Which
For 182 (Queued): Wait for the call to be dequeued. If queuing is not desired, configure the server to reject calls instead of queuing them. For 404 (Not Found): Verify the SIP URI or phone number. Check if the user is registered on the correct domain. Ensure the domain is correct.