Help with VPN Troubleshooting

ahmad20

Commendable
Jul 13, 2016
1
0
1,510
I'm trying to setup a VPN connection (PPTP) to my university library but something seems to block the connection.
I'm using a mac OS X EL Capitan. This error is displayed when trying to connect: "A connection could not be established to the PPP server. Try reconnecting. If the problem continues, verify your settings and contact your Administrator."

So I opened Port 1723 on my TP-Link router and the PPTP Passthrough is enabled. My mac firewall is turned off.
I tried to connect through an other router with a different ISP and it connected successfully. So the problem is either in my router or ISP.

Is there any other things on my router that could be blocking the connection?