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 requirements for the plugin header are not met.

Requirements for the header can be found in the Plugin Handbook from WordPress.

Solution:

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

If so, it is advisable to manually re-upload the application to your server. It is best to use an FTP client for this. In some cases, it may happen that files cannot be written correctly.

If you programmed the plugin yourself, check whether the header is correctly specified in your plugin file (see above).