Web site will not display

I wanted to register a hose reel. I have attached the information provided for registering the product. When I entered the URL shown on the card stating that the page could not be displayed. I don't remember the error exactly. The strange part is that I could go to the home page, but if I selected the registration option I got the error. So it made no difference how I tried to go to the registration page I got the same error. I was about to call the manufacture when I decided to try Microsoft Edge. To my surprise the web page opened and I completed the registration. After completing the registration I went back to FireFox to get the error for this question. To my surprise the web page opened correctly. Can you explain what is going on and what I should do if it happens in the future?