apache2 debian9 won't start. what's the matter?

Question

Apache HTTP Server

When restarting apache2 the following error occurs:

Job for apache2.service failed because the control process exited with error code.
See "systemctl status apache2.service" and "journalctl -xe" for details.

in systemctl status apache2.service:

● apache2.service - The Apache HTTP Server
Loaded: loaded (/lib/systemd/system/apache2.service; enabled; vendor preset: enabled)
Active: failed (Result: exit-code) since Tue 2017-10-24 16: 50:38 UTC; 4s ago
Process: 3989 ExecStart=/usr/sbin/apachectl start (code=exited, status=1/FAILURE)
Oct 24 16:50:37 raspberrypi systemd[1]: Starting The Apache HTTP Server...
Oct 24 16: 50:38 raspberrypi apachectl[3989]: Action 'start' failed.
Oct 24 16:50:38 raspberrypi apachectl[3989]: The Apache error log may have more information.
Oct 24 16:50:38 raspberrypi systemd[1]: apache2.service: Control process exited, code=exited status=1
Oct 24 16:50:38 raspberrypi systemd[1]: Failed to start The Apache HTTP Server.
Oct 24 16:50:38 raspberrypi systemd[1]: apache2.service: Unit entered failed state.
Oct 24 16:50:38 raspberrypi systemd[1]: apache2.service: Failed with result 'exit-code'.

Answer 1

Go to apache error log and see what error

Answer 2

I had the same issue. It turned out that I had a wrong link to the config file.
I found out with the command: sudo apachectl configtest , read the reason and fixed it. Here are my logs:
[email protected]:~$ sudo apachectl configtest
[sudo] password for pimpys:
apache2: Syntax error on line 225 of /etc/apache2/apache2.conf: Could not open configuration file /etc/apache2/sites-enabled /admin.conf: No such file or directory
Action 'configtest' failed.
The Apache error log may have more information.
It's clearly written why. I wish you good luck in solving problems.