Hi @foxiladiw3 ,
So, Shopify is telling you that your theme's code is trying to access a file in your theme's 'assets' folder called 'pagefly-header.liquid'. Have you deleted this file?
Have a check. If you have, I would recommend uninstalling and reinstalling the app. (if Page Fly is an app).
Founder @ www.preproduct.io
Test and make sales for future products