Atmail Webmail creates URLs that have trailing path information after the index.php, for example: /atmail/webmail/index.php/mail/auth/processlogin. Most Apache http servers will see the index.php in the URL, discover that the file exists at the given path and execute it while passing the trailing path information (/mail/auth/processlogin in this example) into the PATH_INFO variable which Atmail later processes in order to discover what action it should take.

Now if you are getting 404s with these kinds of URLs (URLs with trailing path information after an existing file name) then all you need to do to resolve the issue is to adjust an Apache configuration directive:

1. Open your httpd.conf and search for the AcceptPathInfo directive. If you cannot find it then it may be in one of the .conf files that get included so search them also (If you cannot find it anywhere then add it to the end of your httpd.conf).
2. This will almost certainly be set to Off so you will need to change it to On

AcceptPathInfo On

3. save the file and restart apache

You should now be able to use Atmail and not get 404s because of the trailing path information. Enjoy!