I have a customer that has been using us to service there controls. It is a Automated Logic Web CTRL system. Another contractor installed it and programmed it. We recently couldn't access the system remotely from the external static IP address anymore. It was coming up with a 502 gateway error. I instructed the customer to contact there IT department and the orginal installing contractor. Right now there playing the blame game and nothing is getting resolved. Now he wants me to come there on Monday to see if I can figure something out. Is there any troubleshooting tips you guys would recommend? I would really like to help this customer out if I can. I know I am probably going to have to work things out with the IT department, but I just want to know some basic things to try and get this resolved. I am going to verify the IP addresses on the local host and in the Web CTRL program on Monday. I am sure my problem is somewhere in the router/gateway.

Thanks