Have you saved a web address (url) that you tried later, only to find it, NOT FOUND?
You are not alone. Individuals who posted their websites for lots of reasons have to removed them.There is now a website you can use to find what has disappeared from the web. The Finder is the Wayback Machine
Let me demonstrate what I use it for. When I was gathering information about my 9th great-grandfather [Nicolas de Guilizasti], I noticed there was a link with information on his daughter [Juana], my 8th great-grandaunt. I saved the link with the intention of later verifying the references. Well, now the link
The original person who posted the webpage can block access, but that is rare. Sometimes a link to the new corrected address is given which is very good.
BTW: The original WABAC machine that Mr. Peabody and Sherman used was a little different.