Failed Apache2 start, no error log

I also just ran in to a similar problem, that is service apache2 reload fails but prints no useful information. This is because the script in /etc/init.d/apache (on Debian, at least) eats the output of the apache2ctl configtest command it runs to sanitize the Apache config.

An easy solution to get a more meaningful explanation for the failure is to run apache2ctl configtest again yourself, which will print the (hopefully useful) error messages to the console.

Syntax errors in the config file seem to cause problems. I found what the problem was by going to the directory and excuting this from the command line.

httpd -e info 

This gave me the error

Syntax error on line 156 of D:/.../Apache Software Foundation/Apache2.2/conf/httpd.conf:
Invalid command 'PHPIniDir', perhaps misspelled or defined by a module not included in the server configuration

Thanks, Tim! Big stumper for me. A few other details others may find helpful:

(Apache2 on Ubuntu 12.04)

I have two sites running on the same server and had just updated the SSL cert for one of them. Upon restarting the server, I got that cryptic message and neither site worked (obviously). I too found the redirect for the log files in the config files. I tracked that down and found the issue (in the log file for the site I had just updated).

My config files are located in /etc/apache2/sites-available

vim or cat the file (cat {filename}) and look for the ErrorLog line. That tells you where to look on your server. cat that file and the error message I found was:

[error] Unable to configure RSA server private key
[error] SSL Library Error: 185073780 error:0B080074:x509 certificate routines:X509_check_private_key:key values mismatch
[warn] RSA server certificate CommonName (CN) `<snip>.com' does NOT match server name!?

I had copied one of my cert files to the wrong directory. I simply moved it to the correct directory and everything was fine on the next start. (tip: where those file should be is also in the config file ;)