When you intend?to insert a slider in a page in your website, it is important to make sure?the corresponding?ID (slider’s ID) exists in?the slider list page. Because, when you remove some sliders, their IDs would not?be re-indexed and the sequence may broke up.
As a result, if you have received?the message?”Invalid slider id. Master Slider ID must be a valid number.”, you might have inserted slider shortcode with wrong slider ID, or after inserting the slider shortcode, you have removed the main slider from the slider list page.
