Beginning with vRealize Automation 7.3, vSphere and NSX endpoints have certificate validation enabled. You can no longer use an untrusted certificate with these endpoints.
Although you can use the "Test Connection" button to validate the certificate thumbprint on these endpoints, if the certificate is generated so that the root certificate in the certificate chain is not self signed, the certificate validation process for these two endpoints can fail and cause a functional failure in data collection, provisioning, or post-provisioning actions.