Webserver (Apache/nginx) configs regeneration fails: Refusing to create symlink

Symptoms

Web server reconfiguration fails:

`2016-09-06T14:27:06+01:00 ERR (3): Apache config (14731684050.68106800) generation failed:  
Execution failed.  
    Command: httpdmng  
Arguments: Array  
(  
    [0] => --reconfigure-domains  
    [1] => example1.com, example2.com, .......  
)  
Details: Empty error message from utility.`

OR

Apache configuration files regeneration fails with the following error in /usr/local/psa/admin/logs/panel.log or in an email to the Plesk administrator:

Details: [2017-08-17 22:23:40] ERR [util_exec] proc_close() failed ['/usr/local/psa/admin/bin/apache-config' '-l' '/var/www/vhosts/system/example.com/conf/httpd.conf:/etc/httpd/conf/plesk.conf.d/vhosts/example.com.conf'] with exit code [101] 
[2017-08-17 22:23:42] ERR [panel] Apache config (15030266170.00499300) generation failed: Template_Exception: Refusing to create symlink '/var/www/vhosts/system/example.com/conf/last_httpd.conf': file with the same name already exists

Cause

Plesk can't create the symlinks "last_httpd.conf" in configuration directories of virtual hosts because files with these names (not symlinks) already exist.

Plesk can create symlinks with these names, but not files.

Resolution

1. Login to the server via SSH.

2. Find a list of domains without generated configuration files:

   # plesk db -Ne "select name from domains where id in (select distinct(objectId) from Configurations where status='error' and objectType='domain');" > domains.list

3. Remove or rename config files from the error:

   # rm /var/www/vhosts/system/example.com/conf/last_httpd.conf
# rm /etc/httpd/conf/plesk.conf.d/vhosts/example.com.conf

4. Reconfigure domains one-by-one:

   # cat domains.list | while read i; do /usr/local/psa/admin/bin/httpdmng --reconfigure-domain $i; echo "$i - success"; done