Here is the situation,
A,B,C are three different SHAW internet CX,
A is fiber internet cx, setup VPN on his own router, testing pass;
B is using modem Hitron CGNM-2250, using VPN without any problem when connect to home wifi;
C is using modem XB6, got error message when trying to connect VPN; Screenshot attached.
At the same time, VPN works with other WIFI.
I don't find any settings in XB6, and still got the same issue even disabling firewall in XB6
It seems that XB6 is blocking VPN.