Because you say "When I ping google public dns, the first hop is the provider's switch"
Can u try the following?
1) Delete the VPN adapter
2) add this rule in the registry
For Windows Vista, 7, 8, 10, and 2008 Server:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\PolicyAgent
RegValue: AssumeUDPEncapsulationContextOnSendRule
Type: DWORD
Data Value: 2
3) reboot
4) add the vpn connection again and try to connect.