Working with two different MQTT brokers

We are currently using lora server project modules with RabbitMQ broker on the same server (NO mosquito configured). We wanted to know if it is possible to use an external MQTT broker to connect the applications with the lora app server and keep the RabbitMQ broker for the internal communication between lora gateway bridge and lora server?

Yes, that should work without any issues. See also the architecture overview:

Thanks for the fast reply,
We have currently tried to use two virtual hosts on RabbitMQ (theoretically it should be like two different mqtt brokers), one for the communication between lora gateway bridges and lora server and the other one for the lora app server. We tried this by changing the mqtt Username and Password for the lora app server. Once we make this change the system doesn’t work anymore and the nodes don’t get the acknowledge back.

Did you ever resolve this? I’m using RabbitMQ and seeing a similar issue, but I’d rather get RMQ working so I know the infra will scale than rely on mosquitto…