Port Forwarding troubles?

I'm trying to open up a Minecraft server so my friend can join. I have done all the steps I was instructed to follow from numerous videos on youtube, yet the port can't be accessed. I have a Linksys E2500 router, with Timewarner/Fioptics as the internet supporter. I have McAfee Anti-virus, but I turned off the firewall through that. I'm not sure what else I can possibly do. I've been using canyouseeme.com to check whether or not the portal can be accessed. I also have MC and the server running when I try checking it. I really don't know what else it could be, unless Timewarner doesn't allow it, or something. Any help would be greatly appreciated.