DNS pfSense

I need a Networking, DNS or DNS related experience person to solve my issue, I believe this to be the issue (although I’m not certain). EQUIPMENT: -pfSense 2.3.1-RELEASE-p5 (i386) FreeBSD 10.3-RELEASE-p3. -Time Warner Cable (TWC) supplied router Arris TG1672G in bridge mode. -Netgear Router Nighthawk X6 R8000, again in bridged mode and only using wireless features. I use 4 of the available ports to connect other devices (laptop, printer, local server). ISSUE: I can not connect to certain domains hosted on a off-site physical server running linux CentOS, which coincidentally is owned by me. I can access the internet and browse a number of other public websites on my desktop, laptop and iPad.. I can successfully connect to the plesk control panel on the server, however I cannot connect to any website that resides within it. Really weird. THINGS I’VE TRIED: -Verified that the domains are working. They can be accessed from a cell phone using the providers data rather than my wireless network. -Reset the cache in Safari, Mozilla. -Reset the cache in pfSense. -Reset and factor reset numerous times the TWC router, pfSense router, and the NetGear Nighthawk. -Performed ping test from laptop using Terminal on Mac and all tests returned successful. -Removed all pieces of hardware then connected laptop directly to TWC router and was SUCCESSFUL in connecting to the domains in question. This is why I believe it might be related to pfSense settings. WHAT COULD HAVE CAUSED THIS ISSUE: The system had been working correctly up until last week. The only change that was made was that I upgraded the pfSense to v 2.3.1. Prior to upgrade I had the version that did not have the new GUI design. Could this be the reason? If so, how to roll back changes to confirm or deny this hypothesis? WHAT I THINK MIGHT BE THE ISSUE: I think this might be related to a DNS issue. Although, truth be told, I’m not at all experienced enough to understand the technical details of how DNS works. I have SSH access to pfSense as well as the GUI. Do you have extensive troubleshooting experience in pfSense?