DevOps - Value cannot be null. Parameter name: securityNamespace.

Question

DevOps - Value cannot be null. Parameter name: securityNamespace.

Serhii Velychko 0

Hello!

In Azure DevOps, I am trying to create Service hooks - Web Hooks - Release deployment completed trigger, stay all default settings, paste my URL and I get a Subscription Error

Value cannot be null. Parameter name: securityNamespace.

Other webhooks triger types like Build completed or Pull request created was created successfully.

Please, help to solve this.

Pravallika KV 16,700 Reputation points Microsoft External Staff Moderator

2026-02-16T12:00:18.4333333+00:00
Hi @Serhii Velychko ,

Thanks for reaching out to Microsoft Q&A.

Please check if below steps helps to resolve the issue:

Ensure that your Azure DevOps account has the necessary permissions. You may need Project Collection Admin rights to create service hooks.

OAuth Token: Verify that the "Third-party application access via OAuth" is enabled in your Azure DevOps organization settings. You can check this by going to:

Your Azure DevOps organization =>"Organization settings" =>"Policies" under "Security" =>Ensure "Third-party application access via OAuth" is turned on.

Make sure you're logged into the correct Azure DevOps account and that it's associated with the tenant you intend to use. Sometimes, users may accidentally use an account from a different tenant.

Since you mentioned that other webhooks created successfully (like Build completed or Pull request created), double-check if any specific settings are needed for the Release deployment completed trigger.

Connector Setup: If none of the above steps work, consider revoking the current permissions for Microsoft Security DevOps and re-initiating the setup, which can sometimes resolve hidden configuration issues.

Hope this helps!
Serhii Velychko 0 Reputation points

2026-02-16T12:14:33.29+00:00

Thank you for answer! @Pravallika KV
All settings are good. I have Org Admin permissions.

This error appears with all release triggers:
Release abandoned
Release created
Release deployment approval completed
Release deployment approval pending
Release deployment completed
Release deployment started

Also, it happens with all projects (not one).
I created new user account, add it to DevOps, give full permissions and error still the same...
Pravallika KV 16,700 Reputation points Microsoft External Staff Moderator

2026-02-16T12:23:50.6533333+00:00

Go to Organization Settings=>Pipelines=>Settings, check if the option "Disable creation of classic release pipelines" is ON, turn it OFF.
Serhii Velychko 0 Reputation points

2026-02-16T12:29:34.2366667+00:00

@Pravallika KV
It's in OFF state
Praveen Kumar Gudipudi 2,290 Reputation points Microsoft External Staff Moderator

2026-02-26T13:49:47.94+00:00
Hello @Serhii Velychko ,

Few customers are able to resolve this by adding the following property to the CacheBeta task.

securityNamespace:cache

Please go through Value cannot be null. Parameter name: securityNamespace and let us know with an update.
Serhii Velychko 0 Reputation points

2026-02-27T15:05:27.44+00:00

@Praveen Kumar Gudipudi
Thank you!
I saw similar topics on github, describing problems with the pipeline, but mine works successfully. And tell me please, in which build should I add it, what fields should I fill in here, how will it affect others? If I need this webhook for all release deployments...
Praveen Kumar Gudipudi 2,290 Reputation points Microsoft External Staff Moderator

2026-02-27T15:16:58.34+00:00
Hello @Serhii Velychko ,

Are you using:

Classic Release Pipeline (separate Releases section)

YAML multi-stage pipeline (in Repos)
Serhii Velychko 0 Reputation points

2026-02-27T15:21:30.77+00:00

@Praveen Kumar Gudipudi
Classic, I was talking about this fields
Praveen Kumar Gudipudi 2,290 Reputation points Microsoft External Staff Moderator

2026-02-27T16:20:30.5833333+00:00
Hello @Serhii Velychko ,

Before doing this, we need small confirmation, could you please try below steps and provide the update,

Toggle Releases Feature

Project Settings → Overview → Features Turn Releases OFF, save Turn Releases ON again Retry

Create a Brand-New Classic Release

Create new Classic Release pipeline

Add one environment

Run one deployment

Retry Service Hook with:

Any release pipeline

Any environment

If it still fails → backend issue confirmed.
Serhii Velychko 0 Reputation points

2026-03-02T09:33:59.88+00:00

@Praveen Kumar Gudipudi
Thanks,
I tried all the recommended steps, the error is still the same.
Praveen Kumar Gudipudi 2,290 Reputation points Microsoft External Staff Moderator

2026-03-04T07:24:12.3133333+00:00

Hello @Serhii Velychko ,

Thank you for the confirmation.

I have also initiated a private message. Please check it and provide the necessary information so we can continue investigating the issue.
Praveen Kumar Gudipudi 2,290 Reputation points Microsoft External Staff Moderator

2026-03-16T08:26:52.13+00:00
Hello @Serhii Velychko ,

Since GET requests are returning the existing subscriptions successfully, the Service Hooks API itself is accessible. The error you are seeing:

There is no registered handler for the service hooks event type

usually indicates that the event type you are trying to register is not available in the current project context in Azure DevOps.

For the Release deployment completed trigger, the event handler is only available when Classic Release pipelines are enabled and present in the project. If the project only uses YAML pipelines or does not contain any Classic Release pipelines, Azure DevOps cannot resolve the required release security namespace and the subscription creation fails with errors like:

Value cannot be null. Parameter name: securityNamespace

There is no registered handler for the service hooks event type

Could you please check the following:

Navigate to Pipelines → Releases and confirm that Classic Release pipelines are enabled in the organization.

Verify that the project contains at least one Classic Release pipeline.

After confirming the above, try creating the Service Hook again from Project Settings → Service Hooks or via the REST API.

If Classic Releases are not used in your project, the Release deployment completed event will not be available. In that case, you may need to use a Build/Pipeline completed event instead.
Serhii Velychko 0 Reputation points

2026-03-16T08:55:55.88+00:00

@Praveen Kumar Gudipudi
Hello,

As I mentioned month ago, we have many classic release pipelines in this project.
I confirm again that the Classic Release pipelines are enabled in the organization.

Problem still the same...
Serhii Velychko 0 Reputation points

2026-03-23T08:43:43.3533333+00:00

Hello!
The problem is still relevant.
Can the backend DevOps team solve it?
Praveen Kumar Gudipudi 2,290 Reputation points Microsoft External Staff Moderator

2026-03-31T16:34:03.5033333+00:00

Hello Serhii Velychko,

Could you please check the private message and provide the required details for troubleshooting the issue further.

Here is the reference link on how to access & data retention policy of private messages in Microsoft Q&A.
Serhii Velychko 0 Reputation points

2026-06-08T11:49:38.0733333+00:00

@Praveen Kumar Gudipudi
Hello, please tell me if there are any updates?
Praveen Kumar Gudipudi 2,290 Reputation points Microsoft External Staff Moderator

2026-06-09T07:16:03.9133333+00:00

Hello Serhii Velychko,

Could you please check the private message and provide the required details for troubleshooting the issue further.

Here is the reference link on how to access & data retention policy of private messages in Microsoft Q&A.
Serhii Velychko 0 Reputation points

2026-06-09T08:02:11.53+00:00

@Praveen Kumar Gudipudi
Hello, answered in private messages.