WordPress Solution: Updating failed. Error message: The response is not a valid JSON response. Updating failed. Error message: The response is not a valid JSON response.

In your wp-config.php add the following code, preferably on top

define( 'FS_METHOD', 'direct' );

Also, see if your write permissions are good. Here is how to do that via FTP

WordPress: Fastest Way to update all plugins using WP CLI

Use wp plugin update --all to update all WordPress plugins from WP CLI. It’s a lot faster than the WP admin interface.

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