Your ASN is already in use. Please enter a new ASN or delete all existing MCC resources associated with this ASN to unlock it.

Question

Your ASN is already in use. Please enter a new ASN or delete all existing MCC resources associated with this ASN to unlock it.

A T M Maniruzzaman 0

Dear Support Team,

I hope you are doing well.

I am facing an issue during Operator Verification for MCC. The system shows the following error message:

“Your ASN is already in use. Please enter a new ASN or delete all existing MCC resources associated with this ASN to unlock it.”

Our ISP details are as follows:

ISP Name: Pipex Network ASN: 134712

We are the legitimate owner/operator of this ASN, but currently we are unable to proceed with the verification process.

Kindly check from your end and help us unlock/remove any existing MCC resources associated with ASN 134712 so that we can complete the Operator Verification successfully.

Please let us know if you require any additional documents or verification from our side.

Looking forward to your support and resolution.

Best regards, A T M Maniruzzaman Owner, Pipex Network

0 comments

3 answers

Your answer

Answer 1

Hi A T M Maniruzzaman ,

Thank you for your patience.

"Your ASN is already in use" error occurs because your ASN is still registered to a Microsoft Connected Cache resource on our backend. Normally, deleting all MCC resources releases the ASN automatically — but in your case we've confirmed no MCC resources remain on your side, which indicates a stale ASN registration that must be cleared by our engineering team.

We have raised an ASN unlock request to the Product Group with your ASN, subscription, and tenant details. At this time, we are still awaiting an update from the Product Group regarding the ASN unlock request. As soon as the association is released on the backend, you'll be able to re-enter your ASN and complete sign-up. We'll update you the moment we hear back, and we appreciate your patience in the meantime.

Answer 2

kagiyama yutaka 5,330

I think ASN 134712 just stays locked as long as MCC shows “in use.” If it doesn’t show up under Peering or Registered ASN, you basically move on to sending support the ASN ownership.　

A T M Maniruzzaman 0 Reputation points

2026-05-29T04:23:53.8633333+00:00

ASN 134712 belongs to my ISP, Pipex Network, and MCC currently shows the ASN as "in use" during operator verification. The ASN does not appear under my Peering or Registered ASN resources, so I am unable to manage or remove any existing association from my side.
kagiyama yutaka 5,330 Reputation points

2026-05-29T13:30:26.3866667+00:00

I think ur situation lines up with what MCC shows, and the next step is sending Microsoft Support your ASN ownership so they can clear the association.

Answer 3

The error indicates that ASN 134712 is already associated with existing MCC (Microsoft Connected Cache or related) resources, and Azure requires those resources to be removed before the ASN can be reused for a new Operator Verification.

From the available commands and APIs:

Use Azure Peering/MCC management tools to locate existing ASN usage
- If managing peering via Azure CLI, list or inspect peer/registered ASNs to confirm where ASN 134712 is in use.
- For example, if the ASN is registered under a peering resource, az peering asn show can be used when the peer ASN name is known:
```
     az peering asn show --peer-asn-name <peer-asn-name>
```
- For registered ASNs under a specific peering, use:
```
     az peering registered-asn show \
       --resource-group <resource-group> \
       --peering-name <peering-name> \
       --registered-asn-name <registered-asn-name>
```
- These commands help identify which peering/MCC resources are currently bound to ASN 134712.
Remove the existing ASN association if it belongs to the same subscription/tenant
- Once the relevant peer ASN object is identified, it can be deleted with Azure CLI:
```
     az peering asn delete --peer-asn-name <peer-asn-name>
```
- This frees the ASN so that it can be reused in the MCC Operator Verification flow.
- Be aware that deleting a peer ASN or related peering resource can impact existing peering or MCC traffic; ensure that no production dependency remains before deletion.
If the ASN is tied to another tenant or unknown MCC resources
- If the ASN is in use under a different Azure subscription/tenant or by legacy/unknown MCC resources that cannot be managed directly, this must be handled by Microsoft support.
- Open a support ticket from the Azure Portal under the subscription used for MCC/Peering, providing:
  - ASN: 134712
  - ISP/Operator name (Pipex Network)
  - The exact error message from MCC Operator Verification
  - Any proof of ASN ownership (for example, RIR registration details)
- The support team can locate and remove or unlock any stale or conflicting MCC resources associated with ASN 134712 on the backend.
Ensure ASN and prefix requirements are met
- When re-registering the ASN and associated prefixes for Azure Peering/MCC, ensure that all technical requirements are satisfied so validation succeeds:
  - Prefixes must not be in private ranges.
  - The origin ASN must be registered in a major routing registry.
  - Prefixes must be announced from all required peering sessions.
  - Routes must carry the Peering Service community 8075:8007.
  - AS paths must not exceed length 3 and must not contain private ASNs or AS prepending.

Once the conflicting MCC/peering resources are removed or unlocked by either direct management (CLI) or Microsoft support, rerun the MCC Operator Verification using ASN 134712.

References: