Internet connection gets killed after connecting to VPN

[patientx]

Hi there. I have a VPS on USA and been using softether on it for like 3+ years now. I am mostly using VPN on my windows 10 pc and since last week something is going wrong. After I connect to VPN and visit a webpage it just hangs in there sometimes shows the page but later I see that my internet connection gets down-dsl connection cuts- BUT if I use the VPN with my cellphone's 4G network, (in the cellphone itself or setting up a personal hotspot with usb to my PC) VPN works, connection doesn't drop etc. Now how can I find the root cause of the problem here ?