Your Post doesn't contain enough information for me to determine a course of action. Since the FAX isn't working what happens when a regular voice call is attempted across this network layout?
Since we haven't heard back from you we assume you resolved the issue or called tech support for assistance. I went ahead and flagged this post as "Assumed Answered". If you still need assistance, we would be more that happy to continue working wiith you. Just let us know in a reply.