How to fix "unable to get local issuer certificate" in MongoDB

Troubleshooting guide for resolving SSL certificate validation errors when configuring encryption-at-rest with MongoDB Enterprise Advanced and KMIP integration. The root cause was mismatched encryption algorithms in the certificate chain - the KMIP server used RSA while provided certificates used ECC. Includes practical openssl commands for testing SSL handshakes and analyzing certificates, plus an overview of MongoDB Enterprise features and Ops Manager.