## Installation

### Error: /webwork2/instructorXMLHandler: Forbidden

by Michael Gage -
Number of replies: 0
This error

Error: /webwork2/instructorXMLHandler: Forbidden

crops up periodically -- usually while viewing the Library Browser but also while displaying all of the problems in a homework set. These actions involve AJAX (asynchronous javascript and XML) calls from the html page back to the server to fetch new data for part of the page. In this case the rendered contents of each problem to be displayed. The error message above means that for some reason the callback has been refused by the server. Some additional information is available if you have access to and can inspect the server's error log.

(1) The most frequent cause of this is that the $site_server_url value in file webwork2/conf/site.conf is set incorrectly. For example http://mysite.edu is used instead of https://mysite.edu or vice-versa. Browsers can self-correct the url if they get an error message on the first try but the AJAX calls simply fail so it is important that the$site_server_url be exactly correct.

(2) A recent occurrence of this error was due to the fact that in the Apache httpd.conf file the requests addressed to https://mysite.edu were automatically redirected to https://mysite.edu/webwork2 (presumably to make the url easier to remember and/or type). In this case way the redirection command was written meant that calls to https://mysite.edu/mod_xmlrpc (the address for AJAX calls) was redirected to https://mysite.edu/webwork2/mod_xmlrpc and that caused the instructorXML error. It took a while to track down.

There are other issues that can cause the AJAX call to fail, some of them remain a mystery.