Windows 10: VPN stopped working

Hello everyone!
This is my very first post so I am sorry for any mistake.
I have a bothering problem. My VPN, which I configured through the "Settings" page of Windows 10, stopped working. It happened already yesterday, then I restored the system to a previous point and then it worked again. Now it has just stopped once more.
When I try to connect to my configured VPN, the writing "Verifying access information" hangs on, then nothing and then a red writing like "Unable to establish a connection with remote computer. The port used for connection has been closed" appears (more or less this, considering I have it in my own Language). Then, even if I configure another VPN, exactly the same thing happens.
Can it be something corrupted? It would be very strange, considering it happened also yesterday and in both cases I was doing really nothing, it just stopped working.
Any idea? Thank you very much!

P.S.: I have already done network reset and uninstalled and reinstalled network adapters. The only thing that worked, even if just for a while, was restoring the system to a previous point.

:)

 

Cisco VPN stopped working

Cisco VPN stopped working after Update for Windows 10 Version 1607 for x64-based Systems (KB3176936) (2016.09.30.)

It has been running through DELL SonicWall global VPN,
but after the renewal stopped.

I Reinstalled CISCO VPN on
Dell SonicWall but the result
is not.

 

vpn problem

Hey .. I have a problem with vpn .. It was working good but it has stopped working .. Downloaded vpn apps and the vpn options doesn't work anymore .. When I try to connect it says " authentication error " and I don't know what to do ... Can anybody help
me please !!!?