Apache fails to generate configuration: Cannot load modules/mod_proxy.so into server: /etc/httpd/modules/mod_proxy.so: undefined symbol: ap_check_pipeline

Symptoms

• The LiteSpeed server is installed and enabled.
• Apache configuration fails with the following error:

PLESK_ERROR: New configuration files for the Apache web server were not created due to the errors in configuration templates: httpd_ls_bak: Syntax error on line 56 of /etc/httpd/conf/httpd.conf: Syntax error on line 2 of /etc/httpd/conf.modules.d/00-proxy.conf: Cannot load modules/mod_proxy.so into server: /etc/httpd/modules/mod_proxy.so: undefined symbol: ap_check_pipeline. Detailed error descriptions were sent to you by email. Please resolve the issues and click here to generate broken configuration files once again or here to generate all configuration files. See the details in Configuration Troubleshooter

• rpm -V shows modified binaries:

 rpm -V httpd-2.4.6-98.el7_9.6.cloudlinux.x86_64
	.......T.  c /etc/httpd/conf.modules.d/00-base.conf
	S.5....T.  c /etc/httpd/conf.modules.d/00-mpm.conf
	S.5....T.  c /etc/httpd/conf.modules.d/00-proxy.conf
	S.5....T.  c /etc/httpd/conf/httpd.conf
	S.5....T.  c /etc/logrotate.d/httpd
	....L....    /usr/lib/systemd/system/httpd.service
	S.5....T.    /usr/lib64/httpd/modules/mod_proxy.so
	S.5....T.    /usr/lib64/httpd/modules/mod_proxy_fcgi.so
	S.5....T.    /usr/sbin/httpd
	S.5....T.    /usr/sbin/suexec
	.M.......    /var/log/httpd

Cause

LiteSpeed server modified mod_proxy.so file.

Resolution

1. 1. Switch Off/Disable LiteSpeed

   2. Run the following command:

      # yum install --reinstall httpd-2.4.6-98.el7_9.6.cloudlinux.x86_64

   3. Verify installation (modified config files are fine):

      # rpm -V httpd-2.4.6-98.el7_9.6.cloudlinux.x86_64

   4. Run the Web Server configuration repair:

      # plesk repair web -v -y