Question: Apache fails to start: undefined symbol: ap_set_content_type_ex
Applicable to:Symptoms- Apache fails to start with an error like this one:
Cannot load /usr/lib/apache2/modules/mod_headers.so into server: /usr/lib/apache2/modules/mod_headers.so: undefined symbol: ap_set_content_type_ex- LiteSpeed is/was installed on the server
CauseIncorrect package configuration from LiteSpeed.
Resolution
Reinstall Apache
1.Connect to the server over SSH
2.Reinstall the Apache components
RHEL-based# yum reinstall httpd
Debian-based# apt reinstall apache2 apache2-bin apache2-data apache2-utils
3.Start Apache
# systemctl start httpd || systemctl start apache2Related toApache