Cisco 831 VPN configuration problem

Cisco 831 VPN configuration problem

How to configure this router that I have opportunity to connect to office network

for exampe (at home) I created connection in my “network connections” window
“to my network at my workplace” using “VPN”

before reconfiguring that router connection worked and now Ican not connect using this routers.

(this is a router problem not servers, because using other belkin router I don’t have this cind of problem)