Apache is downloading php files instead of displaying them

Question

OS and server information:

• CentOS 6.4 (Final)
• Apache 2.2.15
• PHP 5.5.1

I previously had php 5.3.x installed but decided to upgr

Answer 1

Ok... I know that there are 1.000.000 answers to this questions already, - but I have spent at least 6 effective hours, figuring this one out; and I have googled it hundreds of times and not found a single post about it. So I figured that I would add the solution to my problem here.

The conclusion

If I commented these two lines out in my .conf-files in the /etc/apache2/[[SERVER-NAME].conf-file:

php_admin_value engine Off
IPCComTimeout 31

I have no idea what they do or how they got there, - but it is in every one of my .conf-files. And if I remove those lines and ensure that there is a symlink in /etc/apache2/sites-enabled/-folder, then it doesn't download the index.php - and every works as it should.

The entire story

I have VirtualMin installed on an Ubuntu 16.04 VPS. I upgraded to PHP version 7.2. Shortly after that, I updated the Ubuntu-version and struck a 'Kernel Offset: Disabled'-error. So I had to go delete the latest Ubuntu-version, - and when my OS booted up again: BOOM! I got the error that his post talks about: For every site on my VPS, it simply downloaded the index.php instead of showing it.

I tried all kinds of stuff:

• Removed PHP7.2 and installed PHP5.6 (I know now, that the PHP-version has nothing to do with it; it's the apache-configuration that needs work).
• Tried enabling and disabling apache modules, on the existing installation, but without luck.
• Then I removed apache completely and installed it again, where-after the problem was still there!
• Tried playing around with the Virutal Server setup in VirtualMin ( Webmin >> Servers >> Apache Webserver ).
• Checked the configuration on a single Virtual-server ( Virtualmin >> System Settings >> Re-Check Configuration )... This step was pretty nice, since it told which module in Apache was missing; where-after I could enable it with a2enmod [MODULE_NAME]. And I found the module name by Googling around. I had to active about 6-8 modules, before I got past that step in the validation - and it took a couple of minutes before the cache ran out, - so doing this was a tedious step.
• And lastly, I figured out above-written conclusion - together with the symlinks, - and then I got it to work. I had to go through it for every site on my VPS, though.