Hi ! I had to change my kubeconfig and now many of my stacks are completly lost as they’re trying to reach my cluster with old kubeconfig. Have you any idea how could I fix my stacks ?

First, have a look at https://github.com/pulumi/pulumi-kubernetes/issues/2745. A fix for this has landed in alpha just last week and might be helpful for you. You will have to provide a current kubeconfig to your Kubernetes provider. What exactly do you mean when you say "I changed my kubeconfig"? Where and how did you change it?

In my cloud provider I’ve manually reset it

How did you feed it to the Kubernetes provider originally?

It was created automatically by the cloud provider at cluster creation

It's a bit difficult to guide you with so little information. Are you using a managed Kubernetes service? If so, which cloud provider are you on? Are you using the default Pulumi Kubernetes provider or do you instantiate a custom provider within your code (see the docs)?