Peer is not authorized to use remote address and Cyberguard firewalls

One of my customers has a cyberguard firewall that was working perfectly when I configured it in the office. However on shipping it to the customer, it was placed behind a horrible Verizon modem that broke most of the configuration parameters I had put in place. Most of them were fixable straight away, but I’ve never been able to get it to vpn back to the head office. I was getting the error message “Peer is not authorized to use remote address” in the log files.
Various responses in google mentioned I had to add noauth to the /etc/ppp file but this file doesn’t exist on the cyberguard unit. However, using the Advanced section and editing the “pptp.connect to office” file, adding “noauth” (without quotes) to the end of the file, the vpn connection worked.
This isn’t documented anywhere in google that I’ve seen so hopefully this will help someone else.