Apache Configuration Error Code ah00526 occurs when there is a typo or misconfigured setting somewhere in its configuration files.

As part of our Server Management Services, we assist our customers with several Apache queries.

Today, let us see how our techs go about this configuration.

Apache Configuration Error Code ah00526

We can detect this error using apachectl configtest before an invalid configuration loads.

We can also find it with the systemctl and journalctl commands.

Moving ahead, let us see how our Support Techs troubleshoot this with different commands.

• Troubleshooting with systemctl

First and foremost, we need to check Apache’s status with systemctl.

On Ubuntu and Debian derived Linux distributions:

sudo systemctl status apache2.service -l –no-pager

On CentOS and Fedora systems:

sudo systemctl status httpd.service -l –no-pager

Our output will be similar to the following:

● apache2.service - The Apache HTTP Server
Loaded: loaded (/lib/systemd/system/apache2.service; enabled; vendor preset: enabled)
Drop-In: /lib/systemd/system/apache2.service.d
└─apache2-systemd.conf
Active: failed (Result: exit-code) since Wed 2020-07-15 13:45:49 UTC; 1min 37s ago
. . .

Jul 15 13:45:49 f17f01056c5b systemd[1]: Starting The Apache HTTP Server...
Jul 15 13:45:49 f17f01056c5b apachectl[15860]: AH00526: Syntax error on line 2 of /etc/apache2/sites-enabled/000-default.conf:
Jul 15 13:45:49 f17f01056c5b apachectl[15860]: Invalid command 'SSSLCertificateFile', perhaps misspelled or defined by a module not included in the server configuration
Jul 15 13:45:49 f17f01056c5b apachectl[15860]: Action 'start' failed.
Jul 15 13:45:49 f17f01056c5b apachectl[15860]: The Apache error log may have more information.
Jul 15 13:45:49 f17f01056c5b systemd[1]: apache2.service: Control process exited, code=exited status=1
Jul 15 13:45:49 f17f01056c5b systemd[1]: apache2.service: Failed with result 'exit-code'.
Jul 15 13:45:49 f17f01056c5b systemd[1]: Failed to start The Apache HTTP Server.

Here, we can see that Apache is not running because of the syntax error.

This is due to an extra S character at the beginning of the SSSLCertificateFile line in the /etc/apache2/sites-enabled/000-default.conf file.

Hence, editing the file to fix the directive name will resolve the error and allow Apache to start.

• Troubleshooting with journalctl logs

In case the systemctl output does not include specifics of the error, we go ahead with the journalctl command to examine systemd logs for Apache.

To check this, on Ubuntu and Debian-derived systems, we run:

sudo journalctl -u apache2.service –since today –no-pager

On CentOS, Fedora, and RedHat-derived systems:

sudo journalctl -u httpd.service –since today –no-pager

The –since today flag will help restrict the volume of log entries that we need to examine.

We will receive an output similar to the following:

-- Logs begin at Tue 2019-11-05 21:26:44 UTC, end at Tue 2020-06-09 15:13:01 UTC. --
. . .
Jun 09 15:12:28 f17f01056c5b apachectl[3157]: AH00526: Syntax error on line 3 of /etc/apache2/sites-enabled/000-default.conf:
Jun 09 15:12:28 f17f01056c5b apachectl[3157]: Invalid command 'SSLCertificateFile', perhaps misspelled or defined by a module not included in the server configuration
. . .

The first line of output is the AH00526 error. A general error, it relates to an invalid setting or a typo in a configuration file. And the next line explains what caused the error.

In this case it is the SSLCertificateFile directive, which will only be valid if we enable the ssl module.

Invalid SSLCertificateFile directive

If the AH00526 error relates to an invalid SSLCertificateFile directive, we can resolve it by enabling the ssl module and then restarting Apache.

For Ubuntu and Debian systems:

sudo a2enmod ssl
sudo systemctl restart apache2.service

On CentOS and Fedora systems, we ensure that we have the mod_ssl package, and then load the module by adding it to Apache’s /etc/httpd/conf.modules.d directory in a file like this:

sudo yum install mod_ssl
echo “LoadModule ssl_module modules/mod_ssl.so” | sudo tee > /etc/httpd/conf.modules.d/00-ssl.conf
sudo systemctl restart httpd.service

Once Apache reference the module, we restart it using the command that is appropriate to the Linux distribution. The server will start up if there are no more errors in the configuration.

However, if there are more errors, it will continue to report them and attempt to explain why we can’t start the server.

Ubuntu & Debian Output:

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

CentOS and Fedora Output:

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

• Troubleshooting with apachectl

To troubleshoot with Apache’s apachectl utility, we test the Apache configuration using the configtest sub-command.

This tool will parse the Apache files to determine whether it’s valid and, if not, locate incorrect settings in the Apache configuration.

For example, here it explains that the likely problem is that Apache is referencing an empty SSLCertificateFile:

sudo apachectl configtest

Output

AH00526: Syntax error on line 3 of /etc/apache2/sites-enabled/000-default.conf:
SSLCertificateFile: file '/etc/ssl/certs/example.com.pem' does not exist or is empty

Here, the /etc/ssl/certs/example.com.pem file does not exist as the error message notes.

We can add an SSL/TLS certificate to the file, or remove the directive to resolve the issue.

A successful apachectl configtest invocation will result:

Syntax OK

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Conclusion

In short, we saw how our Support Techs troubleshoot an Apache AH00526 syntax error.