Though this
is stated in the clustering guide, I managed to miss it:
The node name of a RabbitMQ broker started from the rabbitmq-server shell script is rabbit@shorthostname, where the short node name is lower-case (as in rabbit@rabbit1, above). If you use the rabbitmq-server.bat batch file on Windows, the short node name is upper-case (as inrabbit@RABBIT1). When you type node names, case matters, and these strings must match exactly.
Note the remote server name is in upper case for the first request, but in lower case for the second:
