Error 404


A so-called 404 error message is generated when a user follows a wrong URL (address). This can be the case for a broken link (the referenced page has been moved, renamed or deleted) or when the address entered is incorrect.

In order to avoid them, the EPFL 404 tool allows you to collect information on the 404 errors generated by your site . It provides the following information :

  • URL
    What was the address searched for that caused the error
  • Referrer
    Indicates where the error comes from. A link in a page for example. The field can be empty if the user has typed the address or if there has been an automatic access (indexing by search engines).
  • #occurences
    Number of times this error is generated for a given address
  • Last occurence
    The last time the error occurred…


View error list

  • In the side menu, choose Tools > EPFL 404

What to do with this information?

The information is only relevant if the referrer is indicated. In this case, there are two options.

  1. The referrer is a page on your own site: Copy the URL and then modify the wrong link on the page in point.
  2. The referrer is a page external to your site: Ask for a redirection of the URL so that the erroneous address points to another relevant page of your site. Just send an email to [email protected] with the following text : Please redirect the [wrong address] to the following [relevant address].

Sorting information

We suggest that you sort the columns to quickly access the information you need. Simply click once on the column header to get an ascending order, a second time to get a descending order … 

The sorting of a column as well as the order is indicated by a small black triangle pointing upwards (ascending) or downwards (descending).


  • We advise you to sort the referrer in descending order to display the non-empty ones first, those on which you can act
  • To sort by number of occurrences and in this case to have a look at the date of last occurrence. Because if the number of occurrences is low and the date is old, it may not be worth asking for a redirection.