BT Business Hub 5 Port Forwarding

[ThisIsStapes]

So I use a BT Business Hub 5 for my company but I'm struggling to get the port forwarding to work.

I'm trying to change the public port 8000 to private port 8000.

Everytime I add the rule and then add it to my device (laptop) I get the error message:

The application has already been mapped to a device with the same public IP address.

Any help? 

[spank]

Hi there,

Check the DMZ link under firewall, if it's enabled then disable.

The predefined rules include a range of ports so if you have another forwarding rule setup using one of the predefined rules it could include port 8000.  Clear out all your rules and start again.

If you have no other rules you might need to factory rest the router.

Thanks