This error may occur when attempting to access applications that have an index.php file (or other index file), but not an index.html or other specified ‘directory index’ file.
For example, phpMyAdmin includes an index.php file upon installation, but not an index.html file.
By default Apache is configured with the following:
<IfModule dir_module>
DirectoryIndex index.html
</IfModule>
…meaning that Apache will only look for directory index files that are named index.html.
So, when attempting to access phpMyAdmin, Apache throws the following error:
[autoindex:error] [pid 20115] [client 10.30.6.80:50800] AH01276: Cannot serve directory /usr/share/phpMyAdmin/: No matching DirectoryIndex (index.html) found, and server-generated directory index forbidden by Options directive
In this case we want to add index.php to the DirectoryIndex directive.
vim /etc/httpd/conf/httpd.conf
Change:
<IfModule dir_module>
DirectoryIndex index.html
</IfModule>
to:
<IfModule dir_module>
Then exit and save the file with the command :wq .
DirectoryIndex index.html index.php
</IfModule>
Be sure to restart Apache:
systemctl restart httpd