Hi Jarrod,
Thank you for letting us know on the issue you are facing.
This is a simple one to resolve.
On the computer where it is installed, you are able to access it on post 8080. However, you are unable to access it from another computer on the same network. This is because the port is not opened to bypass the firewall of the computer, where it is installed.
Create an outbound rule to port 8080(I'm assuming your ADManager Plus is on the default port) on the machine where it is installed and this will resolve the issue.