Convert rsa private to pem format with openssl command
openssl rsa -in server.key -text > private.pem
openssl rsa -in server.key -text > private.pem
openssl pkcs12 -in keyStore.pfx -out keyStore.pem -nodes
openssl x509 -outform der -in certificate.pem -out certificate.der
openssl x509 -inform der -in certificate.cer -out certificate.pem