VPN issues

Hey guys, I need some help -I am a helpdesk personnel for a small company

One user reported that he is unable to connect to VPN with error messages "remote peer is no longer responding" and "failure to enable virtual adapter" --

what I did:
--Enabled VPN network adapter
--Made sure he is inputting his credentials correctly
--Made sure he has an internet connection
--He is connected via Comcast hardwire not wireless
--I turned off windows firewall, trend micro firewall, and super anti spyware
--Advised him to contact Comcast to see if they are blocking VPN incoming traffic --Comcast states that everything looks fine

--Advised him to plug his laptop in via hardwire and when he tries to connect to VPN on his laptop an error message pops up Reason 412: unable to resolve server address.

--He stated that before he had wireless internet and he was able to connect to VPN



Please tell me what I am doing wrong. Your help will be greatly appreciated.

 

As this appears to have happened after a change of network (new router?), the first thing I would check is that the subnet of the network the user is connecting from, is not the same as the network subnet they are connecting to.

For example, if the work's IP addresses are in the subnet 192.168.1.0/24 and the user's home network is also 192.168.1.0/24, the VPN will not work. As with any IP networking, to route properly the you must connect from one subnet to another different subnet.