SIP 204 No Notification vs 485 Ambiguous
SIP 204 (No Notification) is a 2xx Success response, while 485 (Ambiguous) is a 4xx Client Failure response. 204 indicates that the request was successful but the server has decided not to send a NOTIFY for this SUBSCRIBE request. In contrast, 485 means that the Request-URI was ambiguous. The response body may contain a list of possible unambiguous addresses.
Description
The request was successful but the server has decided not to send a NOTIFY for this SUBSCRIBE request.
When You See It
When subscribing to event packages that may not generate immediate notifications, such as dialog or presence packages.
How to Fix
No fix needed. The subscription was accepted but there is no state change to notify about yet.
Description
The Request-URI was ambiguous. The response body may contain a list of possible unambiguous addresses.
When You See It
When the destination address matches multiple users and the server cannot determine which one is intended.
How to Fix
Use a more specific SIP URI. Check the response body for a list of possible matches and select the correct one.
Key Differences
204 is a 2xx Success response, while 485 is a 4xx Client Failure response.
SIP 204: The request was successful but the server has decided not to send a NOTIFY for this SUBSCRIBE request.
SIP 485: The Request-URI was ambiguous. The response body may contain a list of possible unambiguous addresses.
You encounter 204 when when subscribing to event packages that may not generate immediate notifications, such as dialog or presence packages.
You encounter 485 when when the destination address matches multiple users and the server cannot determine which one is intended.
When to Use Which
For 204 (No Notification): No fix needed. The subscription was accepted but there is no state change to notify about yet. For 485 (Ambiguous): Use a more specific SIP URI. Check the response body for a list of possible matches and select the correct one.