Cobra Forum

Question: Error during the reconfiguration of the Apache files in Plesk: Invalid command 'RequestHeader', perhaps misspelled or defined by a module not included in the server configuration


Symptoms

• Execution of the plesk repair web command returns the next error message:

AH00526: Syntax error on line 117 of /etc/apache2/plesk.conf.d/server.conf:
Invalid command 'RequestHeader', perhaps misspelled or defined by a module not included in the server configuration

Cause

All Apache modules are disabled.


Resolution

1.Log into Plesk

2.Go to Tools & Settings > Apache Web Server

3.Enable modules as on the screenshot below and press the OK button to apply the changes:

(https://pix.cobrasoft.org/images/2025/09/30/image-6.png)

4.Log into the server via SSH

5.Execute the command below to repair the Apache configuration:

# plesk repair web