Cannot remote server from Portal

Cannot remote server from Portal

Hello, I'm Salman.

I got a problem when access the PMP server through the portal, let say it is pmp.com. I cannot remote into the server-A through pmp.com. But, when I'm inside the pmp.com server, I'm able to remote server-A through the portal. At the first time, I thought it was the firewall port issue, then I'm allowing all the port to the pmp.com server but still no progress.

Do you know what happened here?