How to set up data source with https to prometheus

Hi.
I set up my grafana on a different machine with prometheus. And prometheus is opened to internet by nginx with HTTPS. I could use https to visit my prometheus, but how to set up it on grafana. I tried to add auth with TLS cert and key, but it always pops up an error “HTTP Error”. How to configure this? Thanks.

I solved this, it is caused by I miss a configuration on prometheus side.