From fabric document create-join-channel, when I execute the command
peer channel create -o orderer.example.com:7050 -c $CHANNEL_NAME -f ./channel-artifacts/
Try adding a entry in the /etc/hosts for the domain in use (usually example.com)
go to terminal: type "sudo /etc/hosts" in the top add in "127.0.0.1 example.com" press ctrl+o to save, confirm with 'y', press ctrl+x to exit.
try again.. should work.