I tried to customize the registration form, by customzing plone-forms macros. Once I added a simple piece of text in the form, I received this error "There was an error loading modal." I removed the text, but the error is still there.
I get the error once I click "register" in the home page
My question is two folds:
How to solve this error?
How to remove a customised page and restore the original as I used to do so in the old versions of Plone
I am using Plone 5.1.5 on windows 8
In general: Look at your browsers console/ log or look at your Plone instances log files. If you get an unauthorized it may not be logged in latter. The most common problem are unauthorized errors after through the web customizations. In this case you can customize by creating an package in the filesystem and customize there. plonecli helps here getting bootstrapped.
So, I am not sure what you customized exactly. But go to ZMI (Management Interface /manage), either in portal_view_customizations or in portal_skins/custom there should be an entry/ a file with your changes. Remove it, its only an overlay of the original (the original was not modified).