The Master slider plugin in wordpress does not work with wordpress 5.5. installed
Seems like you’re having issue with Master Slider - Touch Layer Slider WordPress Plugin by @averta. So, I would suggest to contact with them. You can comment your issue in the item: https://codecanyon.net/item/master-slider-wordpress-responsive-touch-slider/7467925/comments
Or you can even email them using their profile: https://codecanyon.net/user/averta
I’ve also tagged them here, hope they will be happy to assist you.
Thanks so much I downloaded the modified_masterslider.zip and it worked.
Appreciate your help.