RabbitMQ started but can't access management interface

I think you should check a few things:

the management plugin is not enabled by default, you need to run the below command to enable it: (see https://www.rabbitmq.com/management.html)

rabbitmq-plugins enable rabbitmq_management

Also this runs on port 15672 by default, it is possible the server/network is blocking this port. You will need to check that the port is open.

The problem is because you need to enable the plugins in RabbitMQ, in order to enable that open "RabbitMQ Command Prompt (sbin dir)" and run the following command

rabbitmq-plugins enable rabbitmq_management

It will enable all the plugins that is associated with the RabbitMQ. Now open the browser and type http://localhost:15672 it will open a RabbitMQ console login with guest as username and guest as password.

Sometimes, on Windows, it's not enough to do just rabbitmq-plugins enable rabbitmq_management. UI is accessible only after reinstalling RabbitMQ