I have 3 pc's in my office. I can not log into www.thetreasuredepot.com on my network. I could up until my isp went down about a week ago. after it came back up I can not get on this site and my isp blames the website and the website says its the isp. I can access this site from any other pc outside of my office,
Try changing your DNS servers in your TCP/IP settings to 188.8.131.52 and 184.108.40.206 . Your ISP's DNS server might have problems resolving the addresses, those IP's are Google's public DNS service and often solves issues related to that.
Also try appending https://www. to the beginning of the URL. HTTPS traffic is harder to filter.