If you have freshly install ubuntu 16.04 or any version of ubuntu, and then installed fresh apache and php into the system then lets be frank, the error reporting has been turned off by default.
Then the first thing that we do is start our terminal type in php –ini and search for the php.ini file which tells us to be /etc/php/7.0/cli/php.ini and edit the ini file to display_errors. Then we restart the apache server.
But wait! did that solve the issue.
From first hand experience with the situation, that didnt solve anything. We still wont be able to see any php error. The basic step is somewhat misleading. The command php –ini tells us that the ini file is /etc/php/7.0/cli/php.ini , this ini file is for command line interface(cli) usuage of php and not the apache usuage, if you see the phpinfo you may see another picture. There you can see a line telling you that
Loaded Configuration File /etc/php/7.0/apache2/php.ini
So the actual ini file that has been loaded is not /etc/php/7.0/cli/php.ini but /etc/php/7.0/apache2/php.ini.
So edit that ini file instead.
$ sudo gedit /etc/php/7.0/apache2/php.ini
There search for display_errors parameter and set
display_errors = Off
display_errors = On
Also search for error_reporting parameter and set
error_reporting = E_All & ~E_DEPRECEATED ~E_STRICT
error_reporting = E_ALL
Finally save the file and restart apache.
The error should be displaying now.