RPCPORT and --rpcport not working in Latest version: 0.18.0
See the 0.18 release notes (https://bitcoin.org/en/release/v0.18.0#configuration-option-changes):


  The rpcallowip option can no longer be used to automatically listen on all network interfaces. Instead, the rpcbind parameter must be used to specify the IP addresses to listen on. Listening for RPC commands over a public network connection is insecure and should be disabled, so a warning is now printed if a user selects such a configuration.