ICMP stands for Internet Control Message Protocol. This is basically the protocol that the internet uses to send error messages such as if a server, modem, or router could not be reached.
Have you ever been searching for a website online and clicked on a link that was suggested by a search engine only to get the brutal message 403 page can’t be found? Or server can’t be reached. This is what this protocol is used for.
When servers go down they have to have a way to show the user the problem. This is what the different numbers such as 404 mean. This typically means that for some reason the page does not exist anymore. It could be a temporary server error and you can try again in a little while, but if it comes up 404 again that will mean that the page or the blog post has been removed for some reason.
Try navigating to the home page of the website and see if the home page shows up. If the home page is functioning properly, the post was probably removed by the admin for any number of reasons such as improper content or outdated content.
When receiving one of these error messages, you may be automatically redirected to a page that the administrator of the website previously designated these error messages to redirect you to. So if at any point in your web surfing you come across an article, blog post, or website that does not match the description of the link that you clicked on this is what has happened.