How to monitor for a HTTP 200 OK response?

I am trying to set up a API healthcheck against one of our vendors.

The url is: https://rxsx.xxx.com/xapi/healthcheck

This will return a HTTP 200 OK if there API is up and processing. 

I've tried to set it up using the HTTPS monitor by putting in the https://${IP}:${PORT}/xapi/healthcheck using Put and Get but it fails with underlying connection was closed.

How can I monitor this check for HTTP 200 OK?

Thanks,

Kat