Windows 7 via VPN to Netgear Gateway Pro V7610 and Error 13801

[zillah]

Dear Expert



I configured VPN on a client desktop with windows 7 64-bit (its firewall disabled yes disabled ) in order to be connected Netgear Gateway Pro V7610 following instruction in the link below :



https://www.telstra.com.au/content/dam/tcom/small-business/bundles/pdf/telstra-gateway-pro-v7610-con...



I can remote access to Telstra Gateway Pro V7610 via it public ip address using browser with no issue



But whenever I try to establish VPN connection, error below pops up



https://imgur.com/a/0I4J7



What am I missing ?



Thanks