I set up a Drupal 9.2.1 site, which working fine until I set it up as multi-site.

• I have the master site in the main directory for Xampp (C:xampphtdocs) in the master.com directory

• I created six multi-sites in C:xampphtdocsSpeakFreely.comsites with the following sub-directories: site1.com, site2.com, site3.com, site4.com, site5.com, site6.com

• I updated the the C:WindowsSystem32driversetc file

  127.0.0.1  localhost
  127.0.0.1  master.com
  127.0.0.1  site1.com
  127.0.0.1  site2.com
  127.0.0.1  site3.com
  127.0.0.1  site4.com
  127.0.0.1  site5.com
  127.0.0.1  site6.com 
  

• I updated the C:xamppapacheconfextrahttpd-vhosts.conf file

  <VirtualHost *:80>
    ServerName master.com
    DocumentRoot "C:/xampp/htdocs"
  </VirtualHost>
  
  <VirtualHost *:80>
    ServerName site1.com
    DocumentRoot "C:/xampp/htdocs/master.com"
  </VirtualHost>
  
  <VirtualHost *:80>
    ServerName site2.com
    DocumentRoot "C:/xampp/htdocs/master.com"
  </VirtualHost>
  
  <VirtualHost *:80>
    ServerName site3.com
    DocumentRoot "C:/xampp/htdocs/master.com"
  </VirtualHost>
  
  <VirtualHost *:80>
    ServerName site4.com
    DocumentRoot "C:/xampp/htdocs/master.com"
  </VirtualHost>
  
  <VirtualHost *:80>
    ServerName site5.com
    DocumentRoot "C:/xampp/htdocs/master.com"
  </VirtualHost>
  
  <VirtualHost *:80>
    ServerName site6.com
    DocumentRoot "C:/xampp/htdocs/master.com"
  </VirtualHost>
  

• I updated the C:xampphtdocsSpeakFreely.comsitessites.php file

  $sites['site1.com'] = 'site1.com';
  $sites['site2.com'] ='site2.com';
  $sites['site3.com'] ='site3.com';
  $sites['site4.com'] ='site4.com';
  $sites['site5.com']='site5.com';
  $sites['site6.com'] ='site6.com';
  

I cannot access the site content; I always get a 404 error. The other six sites work fine.