SIP 607 Unwanted

What SIP 607 means

The recipient marked the call as unwanted. For a legitimate business making outbound calls this is a reputation signal worth taking seriously, because repeated reports feed the analytics services that decide whether your number gets through at all.

Global failure (6xx)
Sent by The called party, marking the call unwanted
Occasional

What SIP 607 Unwanted actually means

The called party did not want the call, and the response is specifically intended to convey that judgement back into the network rather than merely to end the call. It was added so that unwanted-call reports could be expressed in the protocol itself, which means it carries weight beyond the individual call.

What causes SIP 607 on a business phone system

A recipient used a report-spam functionMany handsets and mobile networks offer a way to mark a call as nuisance, and that report is passed back.
Your number has been reported enough to be labelledOnce an analytics service associates a number with nuisance reports, calls from it are increasingly refused or flagged before they ring. Outbound sales and appointment reminders are especially exposed.
The number presented is not recognisably yoursPresenting a CLI that recipients cannot identify, or that cannot be called back, invites reports.

How to fix SIP 607

Present a number that can be called backA CLI that reaches a real answering point is the single most effective protection against being labelled a nuisance caller.
Check how your number is currently labelledLook your own number up as a recipient would. Our phone number checker shows how a UK number appears and whether it carries a nuisance reputation.
Review outbound calling patternsHigh volumes of short unanswered calls from one number look like nuisance traffic to an analytics engine, regardless of intent. Spread the load across numbers that each answer properly.

Fixing the underlying problem

This page explains the code. These guides walk through the fix in detail.

Questions about SIP 607

What does SIP 607 Unwanted mean?

The person you called marked the call as unwanted, and that judgement was passed back through the network rather than simply ending the call. For a business it is a warning sign, because accumulated reports are what cause a number to be blocked or labelled as spam.

How do I stop my business calls being marked as spam?

Present a caller ID that recipients can identify and call back, keep outbound volumes from any single number reasonable, and make sure that number is answered when people ring it. A number that never answers return calls is the pattern analytics services treat as nuisance traffic.

Related SIP response codes

Source. SIP 607 Unwanted is defined in RFC 8197 and registered in the IANA SIP Parameters — Response Codes. The causes and fixes above are drawn from our own experience supporting UK business phone systems.

All VoIP & SIP codes