Hello

I was just testing your plugin on localhost, it seems to work well but I get the following message

Warning: call_user_func_array() expects parameter 1 to be a valid callback, function ‘gdpruInsertNotification’ not found or invalid function name in C:\xampp\htdocs\mywebsite\wp-includes\class-wp-hook.php on line 286

Can you check it?

Best regards
Elen