Thanks Mark. I think I figured it out, sort of. I have been trying to access the website while I am in my office. I hadn't tried it lately at home, so I did so last night. Everything worked fine on both my home computer and my iPhone. So today at my office I tried it again on my cell phone, and after it still didn't work, I turned off Wi-Fi on the phone and tried again. Using my cell phone’s data connection it worked every time.
It then occurred to me that a few weeks ago my company made some changes to our systems to help fight the recent rash of ramsonware attacks. I theorize that the Wi-Fi connection at my office has some sort of security feature that is preventing certain web pages from loading.
In any event, it is good to know these pages are still out there and accessible when needed (albeit not from my office computer). Thanks again for all the replies!
Dean