Azue K8 Not resolving IP - Getting an error Failed to list *v1.Endpoints: Get

Hi, we have been running K8 in Azure for a while but now we are seeing the following error:
E0702 08:12:09.566147 1 reflector.go:153] pkg/mod/k8s.io/client-go@v0.17.3/tools/cache/reflector.go:105: Failed to list *v1.Endpoints: Get "https://.australiaeast.azmk8s.io:443/api/v1/endpoints?limit=500&resourceVersion=0": net/http: invalid header field value "Bearer -----BEGIN PRIVATE KEY-----\n\n-----END PRIVATE KEY-----" for key Authorization.

I am not sure why we are seeing this error, any help would be great.
Thank you
Paul.