You should add client option to your mysql-connector
allowPublicKeyRetrieval=true to allow the client to automatically request the public key from the server. Note that
allowPublicKeyRetrieval=True could allow a malicious proxy to perform a MITM attack to get the plaintext password, so it is False by default and must be explicitly enabled.
you could also try adding
useSSL=false when you use it for testing/develop purposes