SIP 180 Ringing vs 500 Server Internal Error
SIP 180 (Ringing) is a 1xx Provisional response, while 500 (Server Internal Error) is a 5xx Server Failure response. 180 indicates that the UA receiving the INVITE is trying to alert the user. This response is used to initiate local ringback tone at the caller's end. In contrast, 500 means that the server encountered an unexpected condition that prevented it from fulfilling the request.
Description
The UA receiving the INVITE is trying to alert the user. This response is used to initiate local ringback tone at the caller's end.
When You See It
During call setup when the callee's phone is ringing. You should hear a ringback tone after receiving this response.
How to Fix
No fix needed — the callee's device is ringing. If the call never connects after ringing, check the callee's device or call forwarding settings.
Description
The server encountered an unexpected condition that prevented it from fulfilling the request.
When You See It
When the SIP server has an internal error — database failure, unhandled exception, or resource exhaustion.
How to Fix
Check server logs for the specific error. Common causes include database connectivity issues, configuration errors, or memory exhaustion.
Key Differences
180 is a 1xx Provisional response, while 500 is a 5xx Server Failure response.
SIP 180: The UA receiving the INVITE is trying to alert the user. This response is used to initiate local ringback tone at the caller's end.
SIP 500: The server encountered an unexpected condition that prevented it from fulfilling the request.
You encounter 180 when during call setup when the callee's phone is ringing. You should hear a ringback tone after receiving this response.
You encounter 500 when when the SIP server has an internal error — database failure, unhandled exception, or resource exhaustion.
When to Use Which
For 180 (Ringing): No fix needed — the callee's device is ringing. If the call never connects after ringing, check the callee's device or call forwarding settings. For 500 (Server Internal Error): Check server logs for the specific error. Common causes include database connectivity issues, configuration errors, or memory exhaustion.