This can be caused by one or more of these issues.
The host name or IP address of the remote server configured in the VPN client is incorrect.
The group name and password configured in the VPN Client does not match with the group name and password on the headend device. The group name and password are case-sensitive; these can have been typed incorrectly.
The VPN Client does not have IP connectivity to the remote server, or traffic is blocked by a device between the client and the remote server.
Complete these steps in order to resolve this issue:
Verify that the hostname or IP address for the remote server configured in the client is correct.
Verify the group name and password configured on VPN client. Right-click Connection entry > Modify > authentication tab in order to do this. These must match with the group name and password configured on the remote server.
Ping the IP address of the remove server in order to verify that the VPN Client device has IP connectivity to the remote server.
Check to see that Internet Key Exchange (IKE) or IPsec traffic is not blocked by a device between the VPN Client and the remote server.