>Hi,
>
>Since two days ago I have been having a problem connecting to a customer network via Windows VPN. I get error:
>

>Error 800. The remote connection was not made because the attempted VPN tunnels failed.  The VPN server might be 
>unreachable. If this connection is attempting to use an L2TP/IPsec tunnel, the security parameters required for IPsec negotiation
>might not be configured properly
>

>
>When I shutdown (for 10 min) Avast AV/FW, I can connect, however. I called Avast support but the support person says that Avast does not usually block VPN connections.
>
>Is there a log that will show me what is blocking this VPN connection?
>
>TIA

It's Avast - there are several features of Avast & one of them is 'web shield' or something like that - supposed to be protection from phising sites and block some mailware - anyway try turning that feature off.