https://api-int.ocp4.example.com:22623/config/master x509: certificate signed by unknown authority

I would like to implement Openshift v4.14 (UPI) using the external registries in our lab.

I have encountered the following issue with “x509: certificate signed by unknown authority” while the master nodes are new deploying.

ignition: Get error: Get https://api-int.ocp4.example.com:22623/config/master "x509: certificate signed by unknown authority"

The problem seems to be caused by the self-signed certificate of the api-int.ocp4.example.com. I would like to know how the Master can trust that certificate as the cluster doesn't formed.

Thanks in advance.