Why does the Forbidden You don't have permission to access this resource error occur?

Question

Apache HTTP Server

Here is a config:

<VirtualHost *:80>
  RewriteEngine On
  
  RewriteCond %{REQUEST_URI}   ^/api   [NC]
  RewriteCond %{REQUEST_FILENAME}   !-f
  RewriteRule /api/(.*)   http://l27.0.0.1:4000/$1   [P,L]
  
  RewriteCond %{HTTP:Upgrade}   =websocket   [NC]
  RewriteRule /(.*)   ws://l27.0.0.1:3000/$1   [P,L]
  RewriteCond %{HTTP:Upgrade}   !=websocket   [NC]
  RewriteRule /(.*)   http://l27.0.0.1:3000/$1   [P,L]
  
  ErrorLog ${APACHE_LOG_DIR}/error.log
  CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>

Answer 1

Check if mod_proxy_wstunnel is loaded.
There, in three lines, instead of a number, there is the Latin letter "l".