Error reference

SIP 404 Not Found

Short answer

On an outbound call, a 404 means that the phone network that serves the number says it doesn't exist. Check the number and its format, and try it from a mobile. On an incoming call, the 404 usually comes from your own PBX or Microsoft Teams, because it doesn't recognize the number it was sent.

Applies to
Cloud SIP, Phone Numbers, Teams Direct Routing
Works with
Any SIP PBX or SBC, Microsoft Teams Direct Routing
Who can do this
Whoever manages your PBX and your Enfonica project

Check for a known incident first. If there is one, we're already working on it, and there's nothing to change on your side.

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On this page
  1. What are you seeing?
  2. Outbound calls to a number fail with 404 Not Found
  3. Calls to a number fail with 404 only from one caller ID
  4. A number works from a mobile but fails with 404 through Enfonica
  5. Incoming calls fail with 404 from your PBX or Teams
  6. How do I tell where the 404 came from?
  7. What to send us
  8. Related

What are you seeing?

Outbound calls to a number fail with 404 Not Found

SIP/2.0 404 Not Found

Cloud SIP accepted the call and passed it to the phone network. The network that serves the number then answered that the number isn't assigned.

The response usually carries a Reason header with cause=1 and the text Unallocated (unassigned) number. In Cloud Voice > Calls, the leg to the phone network shows the error code ENDPOINT and the message The endpoint is not connected.

The number is disconnected or doesn't exist

Check

Call the number from a mobile. If it also fails, or you hear a recorded announcement, this is the cause.

Fix

Check the number with whoever gave it to you. If you dial from a list, mark the number as disconnected.

Your PBX changed the number on the way out

An outbound rule that drops or adds a digit can turn the number dialed into a different number. The new number looks valid but isn't in service. A 1300 number is the usual case.

Check

Open the call in the Console, and compare its To number with the number the user dialed. For example, 1300 975 707 sent as +61300975707 instead of +611300975707.

Fix

Correct the outbound rule (dial plan) in your PBX so that it sends the number in full international format (E.164). For examples of every kind of number, see Which number format should my PBX use?

Calls to a number fail with 404 only from one caller ID

SIP/2.0 404 Not Found

Some networks refuse calls that present particular caller IDs, to protect their customers from scam and spoofed calls. They answer with a 404 rather than a clearer code.

The destination network is refusing the caller ID

Check

Call the same number with a different caller ID. If the call works, this is the cause. It's most common on forwarded calls, where your PBX passes the original caller's number through.

Fix

Present one of your own numbers on these calls. If you need the original caller's number to show, contact us with an example, and we'll look at the options for your setup.

A number works from a mobile but fails with 404 through Enfonica

SIP/2.0 404 Not Found

Sometimes a number is in service and rings from a mobile, but calls through Enfonica get a 404, whatever caller ID you use. This means the network that serves the number has a fault with calls that arrive from other carriers.

The destination network has a fault

Fix

Contact us, because this is something we raise with the network. Send us two or three example calls with the details listed below, including a time when the number worked from a mobile. We'll trace them and take it up with the network responsible.

Incoming calls fail with 404 from your PBX or Teams

The endpoint is not connected

On an incoming call, Enfonica delivered the call, and your own system answered 404 because it doesn't recognize the number. In Cloud Voice > Calls, the leg to your PBX or Teams shows the error code ENDPOINT with this message. The SIP trace shows the 404 coming from your system's address.

Your PBX doesn't have the number set up

Enfonica sends the number that was called in E.164 format, for example +61255501234. Your PBX's DID (the number it answers on) or inbound rule must match it in that format.

Check

Look at your PBX's DIDs and inbound rules. This is the cause if the number is missing, or if it's listed in another format, such as 0255501234.

Fix

Add the number in E.164 format, with its leading +, and give it an inbound rule. For this and the other ways a PBX rejects calls, see Calls aren't reaching your PBX.

The number isn't set up in Microsoft Teams

Teams answers 404 when the number isn't assigned in your Microsoft 365 tenant. Callers might hear a busy tone.

Fix

Ask your IT team or MSP to check these settings in your Microsoft 365 tenant:

  • The user has a Teams Phone license.
  • The number is assigned to the user in E.164 format.
  • The user has a voice routing policy.

For the full checklist, see Teams Direct Routing calls fail or don't ring.

How do I tell where the 404 came from?

Open the call in Cloud Voice > Calls, and read its SIP trace:

  • If the 404 came back from the phone network, the call was outbound, and the causes in the first three sections apply.
  • If the 404 came from your PBX's or Teams' address, it's an incoming call that your system refused.

To learn how to read the trace, see Find a call and read its SIP trace. For every other error on outbound calls, see Outbound calls aren't going through.

What to send us

Include these and we can find the call straight away.

  • The number that made the call and the number it called, in full international format (for example +61255501234).
  • The date and time of the call, with your timezone.
  • Whether the call was inbound or outbound.
  • The call ID, if the Console shows the call.
  • What happened: an error message, silence, a busy tone or a dropped call.
Contact support

Our support team are telco specialists, backed by the engineers who run the network.