487 4xx Client error RFC 3261
SIP 487 Request Terminated
The request was ended by a BYE or CANCEL before completion. Usually the caller hung up while ringing.
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Common causes
- The caller hung up before answer.
- Ring-group or queue cancelled other branches when one phone answered.
- A timeout on the caller side cancelled the INVITE.
How to fix it
- Usually normal. If calls are cancelled too soon, raise ring timeouts on the PBX or carrier.
Seeing 487 on calls through a router or firewall? Check that SIP ALG is disabled. It causes a surprising number of SIP errors. Read why.
About 4xx responses
The request has a problem or cannot be completed at this server, usually because of something on the requesting side or the target user.