Azure DevOps Environment Kubernetes Validation Failures — Connection Errors Despite Reachable AKS API

Problem description

I am experiencing validation failures for Kubernetes resources in Azure DevOps Environments that use a generic provider with an existing service account. The error indicates inability to connect to the cluster and namespace, with messages like 'Unable to connect to the cluster and namespace chosen for this resource' and 'Failed to query service connection API: ... Error Message: 'An error occurred while sending the request.'" Despite the AKS API being reachable and the API endpoints being public, the validation fails. I have confirmed that the API is accessible from my network, and the service account has the necessary permissions at the namespace level. I also created a new secret and resource, but the issue persists. The problem affects multiple AKS targets and started without any apparent change in configuration or cluster recreation.

Environment

Azure DevOps Services; Azure Kubernetes Service (AKS); West Europe region; connection type: generic provider using an existing service account; cluster API server endpoints are public; not a private cluster; no API server authorized IP ranges configured.

What I've already tried

I confirmed that the AKS API is reachable from my network. I checked that the existing resources show connection warnings, and created a new Kubernetes resource with a new secret, but validation still fails with the same error. I verified that the service account has the necessary permissions at the namespace level, but Azure DevOps still reports inability to connect. No cluster recreation or certificate rotation has been performed recently.

Current status

I am seeking assistance to identify the root cause of these connection validation failures and how to resolve the issue so that new resources can be successfully validated and created in Azure DevOps Environments.