WordPress’ error message: The plugin has no valid header

The error message is triggered by WordPress. It is located in the file wp-admin/includes/plugin.php at line 1108.

The error is triggered as soon as the plugin header requirements are not given.

Requirements for the header can be found in the WordPress plugin manual.

Solution:

First, you should check if the application is a WordPress plugin.

If so, it is recommended that you manually re-upload the application to your server. The best way to do this is to use an FTP client. In some cases, it can happen that files cannot be written correctly.

If you have programmed the plugin yourself, check if the header in your plugin file is correct (see above).