I am working from home like I am sure ALOT of you are. My husband and I have 1GB internet. We had a storm in the area (Don't think it's related), and now I cannot connect to my companies VPN. I am met "with the following error message:
VPN connection between your computer and the VPN server could not be completed. The most common cause for this failure is that at least one internet device between your computer and the VPN server is not configured to allow GRE protocol packets. If the problem persists please contact your Network Admin or ISP"
Did some minor tweaks and am now met with the following message: 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.
I called Xfinity and they have level 3 handling this. My IT department does not have a stand-alone VPN client so we're using the built in one for Windows.
Try disabling the Xfi Advanced Security feature as a work-around for now and see. It's buggy ! And there is currently no way for an end-user to be able to whitelist anything;
YMMV. Good luck !
Is the VPN working now ?
Then there is more to do. Sorry that didn't work for you. I did say YMMV. Check your firewall(s). Talk to your company's tech support. Good luck with it !
Your Mileage May Vary.