Adding external service in PMM1

I’m trying to add a new data source to PMM 1.17.3. I run the following command on the target server:

pmm-admin add external:service my-core --path /monitor/prometheus --service-port 80

HTTP requests are redirected to HTTPS, but the certificate is only valid for my domain name, while PMM sends requests using IP address. Hence the error message:

x509: cannot validate certificate for xx.xx.xx.xx because it doesn't contain any IP SANs

where xx.xx.xx.xx stands for my IP address.

How do I make PMM to use the domain name instead of IP? Or is there a way to skip certificate validation?