In Long Beach, CA, there’s a store called “The Eye of the Cat” which sells herbs and other stuff supposedly used by witches. (There’s a sign near the counter: “I am a Witch–do you have a problem with that?”)
On a window outside is their web address. I tried to log onto this and got a message “You are not authorized to open this page” and the word “Forbidden” appeared on the blue title bar.
What’s going on here? 
Probably you are getting an HTTP 403 error, which means “access forbidden”. The site may use some method of authentication for controlling access to its webpages (e.g. restricting them to people with passwords).
But more likely, the file permissions are incorrectly configured on the server so that no one can view the site over the internet. Servers are commonly set up so you can’t view a directory: if you have a URL that ends with a slash or just the bare “.com”, rather than a suffix like “.html” or “.htm”, this may refer to a directory rather than a file. Trying to view the directory will give a 403
You could try adding “index.html” or something similar, or emailing the site owner - try webmaster@site.com - to see if it’s accidental, which it might well be.
The most likely scenario is that they forgot to pay their ISP bill, and the ISP simply took their pages offline until they pay up. Either that, or you caught them in the middle of a page update, in which case the site should be available again soon.