What is the meaning of 404 redirect htaccess?

I have a blog website. But recently I am facing a problem with my website. My bloggers, users and friends are unable to gain access the website. I can access the website as an administrator. When others try to gain access it as an user, It shows the error message of 404 redirect htaccess.
What does 404 redirect htaccess actually means? How can I solve this problem?
