Blocked from a website?

[miles93]

At random times, my computer will not give me access to a specific website.  It comes back "problem loading page" or "site not found."  This happens on both my laptop and by Iphone.  Because I have to make business transactions at this site, I have to ask friends to make my purchases on their computers or phones.  I've talked to the program guy who takes orders off the site and he says he hasn't heard from anyone else with this problem and there's nothing he can do.  How can I fix this?

[dslr595148]

#1 What the brand and model of your router?

#2 What are the DNS Servers that you use?

#3 If you use Firefox, see the info at https://support.mozilla.org/en-US/questions/1115951

#4 If you do not use Firefox, what web client/browser do you use?