and I (as a developer) doesn’t have access to insight/pulse/rabbitmq.
Are you using ServiceControl and ServicePulse but you don’t have access to it, or are you generally not using these tools?
If you’re not using ServiceControl at all, the RabbitMQ management plugin would probably be the easiest way to access messages in the error queue.
Btw. the endpoint also logs the exceptions that causes the messages to move into the error queue, so you might also just look at the endpoint’s log files to start with.