If you are not familiar with Apache HTTP error codes and you are looking for the meaning of a given error code (example: "Error 403 forbidden by rule"),
do the following:
- Go to this page
which lists the functions of Apache HTTP module "core"
- Press the link named "ErrorDocument" to display the page regarding error messages
- Scroll down to the table with column headings "Error code" and "Error meaning"
- Look for the error code appropriate to your case and read its explanation in the next column.