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480
4xx Client error, RFC 3261

SIP 480 Temporarily Unavailable

SIP 480 Temporarily Unavailable means the call reached the destination, but the person cannot take it right now: their phone is offline, switched to do not disturb, or out of coverage.

Who sends it
The called side
When
Placing the call (INVITE)
Retry?
Later. The response may carry a Retry-After header with a better time.
The caller hears
Often a message that the person is unavailable, or a failure tone after a short ring.
PBXYour phone or PBX
SIPThe SIP trunk
☎The called sidesends 480
FIX

What causes 480, and how to fix it

480 says the destination exists but cannot take calls at the moment. For mobile destinations it often maps to a phone that is switched off or out of signal.

  1. 1
    Most common

    The called phone is switched off, offline or out of coverage.

    Try again later, or reach the person another way.

  2. 2
    Most common

    For calls to your own number, the SIP login it rings is not registered, so callers get 480.

    Check that the phone, app or PBX behind that login is online and registered, especially after a router restart.

  3. 3
    Sometimes

    Do not disturb is switched on at the called phone.

    If you are calling your own extension, turn off do not disturb or set a forward.

  4. 4
    Sometimes

    Outbound calls work but incoming calls fail, because the router forgets the path to your phone.

    Enable keep-alives on the phone or PBX and turn off SIP ALG, so the path stays open between calls.

LOG

What 480 looks like in a SIP log

SIP/2.0 480 Temporarily Unavailable

Capturing one: reading the SIP log.

SIP response
SIP/2.0 480 Temporarily Unavailable
Via: SIP/2.0/UDP 203.0.113.10:5060;branch=z9hG4bK-74bf9
Call-ID: [email protected]
Retry-After: 300
≠

Not to be confused with

480, 408, 486 or 503?

408

Request Timeout

No answer came back at all. 480 is a clear answer: unavailable right now.

486

Busy Here

The person is on another call. 480 means their phone cannot take calls at all at the moment.

503

Service Unavailable

A server in the network cannot take the call. With 480 the network is fine.

FAQ

SIP 480 questions

Why do callers to my virtual number get 480?
Calls to your number ring the SIP login you chose. If no phone, app or PBX is registered on that login at that moment, there is nothing to ring, so the caller gets 480.
Should I retry after a 480?
Later rather than straight away. If the response includes Retry-After, that is how many seconds the destination suggests waiting.

Not 480? Look up another code.

The full list: SIP response codes. 480 again and again? Check your SIP trunk configuration.

All SIP codesFind a fault by symptom