I have an odd case but I think I know what the problem might be but I want some outside opinions.
I have a user that normally works from home and has no issues with the VPN connection. Today how ever he has gone to a customer location and is unable to connect. My first instinct is that he is behind a firewall that is blocking part of the pptp connection. See what it looks like in the log from my side of things below.
I suspect if I switch him over to l2tp he might work or if I disable encryption it might work but I just want to get outside ideas before I do.
User reported he tried using L2TP and still failing, did not see anything on this side of things.