Steps to reproduce:

1. Monitor a RabbitMQ node using the RabbitMQ Node by HTTP template
2. Set the Visible Name to a value different from the node host name
3. Save the configuration

Result:

Zabbix reports RabbitMQ node: failed to fetch nodes data

That happens because the constructed URI is not correct to retrieve the data:

{$RABBITMQ.API.SCHEME}://{$RABBITMQ.API.HOST}:{$RABBITMQ.API.PORT}/api/nodes/{$RABBITMQ.CLUSTER.NAME}@{HOST.NAME}?memory=true

HOST.NAME is not the node name if Visible name is not set as such (I use a different nomenclature to sort them together easily). Not it is documented it should be.

Expected:
Node data are fetched correcty.

I modified the item URL using a dedicate macro:

{$RABBITMQ.API.SCHEME}://{$RABBITMQ.API.HOST}:{$RABBITMQ.API.PORT}/api/nodes/{$RABBITMQ.CLUSTER.NAME}@{$RABBITMQ.NODE.NAME}?memory=true

where $RABBITMQ.NODE.NAME can be set to the correct node name, regardless of the Visible name.