Intermittent Website Issues, Tracert Results

Hi all,

Small business owner using Comcast and from time to time, our network loses access to our own website. Website is hosted externally but for people on our local network, website is inaccessible. It's important to note that if you're on your phone (cell data) or on another network, website is up the entire time.

I'm thinking there is some IP filtering going on but can't figure out if it is my router issue, a Comcast issue, our host server's ISP, or our hosting server itself. 

Tracert of website when working and when it isn't working are linked via screenshot in a word document on dropbox here:  https://dl.dropboxusercontent.com/u/18916052/Internet%20Troubleshoot.docx