cannot view our website

our ISP hosts our domain website and it’s still live. however, for some reason we are no longer able to view our home pages from inside the network, but we can see it offsite. i am not sure if it caused by new added cisco firewall or some other changes. please help. (btw, we are able to see if typing in “ourdomain.com.ISP.net” instead of “ourdomain.com”)