Configure the Data Collector to trust the certificate
In cases where the certificate authority (CA) is not trusted, as may be the case when using a self-signed or unknown certificate, both the Data Collector and the Upgrade Manager will need to have the certificate imported into the keystore to ensure that the Data Collector can communicate using SSL.
See Keystore file locations on the Data Collector server.
See Import a certificate into the Data Collector Java keystore.