shortcode from plugin causes The response is not a valid JSON response Error

Hello guys, I have a shortcode create from my custom plugin.
This is how I create that shortcode from plugin:

class test_plugin{
	function __construct()
            register_activation_hook(__FILE__, array($this, 'plugin_activation'));
            register_deactivation_hook(__FILE__, array($this, 'plugin_deactivation'));
            register_uninstall_hook( __FILE__, 'plugin_uninstallation' );

        public static function my_custom_view_handler(){
            echo '<div>My view</div>';
$test_plugin = new test_plugin();

After activating plugin, I created new page and added shortcode to shortcode block like this [‘my_custom_view_shortcode’].
And now, whenever I press publish or update button in any page/post which contains my custom shortcode [‘my_custom_view_shortcode’] will give me the error ‘Publishing/Updating failed. The response is not a valid JSON response.’
I reloaded my page, all information was still saved in database and showed expected result ‘<div>My view</div>’.
Can you help me how to fix that error? Thank you

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