Having problems with my page being blocked outside the network...

[J_ZeFF]

Okay... hopefully i can explain this good enough.
I have been recently hired as "the IT guy" for a small company, and im learning as i go. So try and take it easy on me, haha.

Our company uses a CRM sales software called ACT! premium.
ACT is essentially a program that tracks interactions between our sales agents and customers and potential customer. Its a big SQL database.

The new version of ACT that we just got has web access. This means that by going to a certain IP address from any browser/mobile device you can login to your ACT account and make changes. The web server software has been installed by an ACT Certified Consultant, the server settings and the router settings are all 100% correct.

My problem... When i go to that IP address from a computer outside of the network it shows BAD REQUEST (INVALID HOSTNAME) When i ping the IP address it times out. When i remote into my server that the software is installed on and go to whatismyip.com i get the ip address, but i also get "possible proxy detected: 1.1 white:
White is one of the servers that we have, and i understand what a proxy is, but i dont know how to allow access to that IP address from outside the network.

Something is blocking outside access to the page, but i have no idea what it is. What could it be?

Thank you so much in advance for contributing to this, my boss is really getting frustrated.

[J_ZeFF]

I explained the problem to the old IT guy over text message and he told me i had to "configure iis headers on the server"

Maybe someone can elaborate on that one for me.
I have never done anything with iis headers...

There is a language barrier between me and him, so it makes things more difficult.

[jdeb]

configure iis headers - Google Search