It's going to be hard for people here to help you without knowing the actual domain name. (And using a placeholder name that's someone else's name makes things even weirder.)
But yes, it seems likely that your firewall is blocking requests from parts of the Internet, but not from where you're testing from.
You may want to try some of the online tools listed under "What tools are out there to help check my domain's accessibility from around the world?" in this FAQ: