When performing a System SSL transfer the following message is displayed:
XCOMM1510E System SSL Function gsk_environment_init(env_handle): RC = 202: Reason = Error detected while opening the certificate.
After reviewing the XCOM trace we found the actual message returned by IBM's System SSL, which was: "RC = Key entry does not contain a private key"
Ensure that the ICSF started task is started before the application if the private key is stored in ICSF. When using z/OS PKCS #11 tokens, ensure that the user ID has appropriate access to the CRYPTOZ class.
If executing in FIPS mode, ensure that the certificate that is being used does not have its private key stored in ICSF.
Here is the explanation from IBM's knowledge center: