Prometheus remoteWrite not working

Hi, I am trying to configure remoteWrite in kube-prometheus-stack helm chart. The values.yaml file of helm chart contains this -

- url: ""
    username: XXXXXX
    password: "<token>"

After installing the chart I get this error in prometheus operator pod - “caller=stdlib.go:105 caller=server.go:3158 msg="http: TLS handshake error from SomeNodeIP:SomePort: remote error: tls: bad certificate” and no data is getting sent out.
I’ve tried to push metrics to my on premise cortex cluster but still getting the same error.

Actually, I am getting this error irrespective of whether I provide a remoteWrite url or not. I can’t find any logs regarding remoteWrite in the pods.