Hell,

I would recommend a few things in this case:

• Check if there are any errors in your config files by running a config test:

apachectl -t

If you have any config errors the above command would point you to the correct direction for further troubleshooting

• Check the status of your Apache:

systemctl status apache2

This could also give you some very useful information

• Check your Apache error log:

tail -100 /var/log/apache2/error.log

The above steps should provide you with all of the necessary information to get the problem fixed.

Hope that this helps!
Regards,
Bobby