Postfix and OpenJDK 11: “No appropriate protocol (protocol is disabled or cipher suites are inappropriate)”
I was facing the same issue using JDK 11. But I resolved it by commenting this line in the java.security file: jdk.tls.disabledAlgorithms=SSLv3, TLSv1, TLSv1.1, RC4, DES, MD5withRSA, DH keySize < 1024, EC keySize < 224, 3DES_EDE_CBC, anon, NULL, include jdk.disabled.namedCurves