Cannot use index.php in mod_rewite

[Kroptokin]

I've just migrated a domain to a new server. From CentOS 6.5 to Centos 7.2

Mostly it has gone pretty well. But in one domain I am unable to use index.php in mod_rewrite.

This is the .htaccess file:

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

With this configuration I get the default 'Welcome to Plesk' page. I also see Got error 'Primary script unknown' in the error logs, which may or may not be related.

If I change index.php to (say) home.php everything works as expected.

So. There is some specific configuration issue with index.php.

I tried switching from running PHP as FPM to FastCGI as some threads seem to suggest that as a possible solution but that didn't help.

Does anyone have any ideas?

 

[Kroptokin]

RESOLVED.

Stupid error. index.html was present in the directory. It looks like there must be a DirectoryIndex directive somewhere to serve index.html if it exists.