wordpress customize "warning" instead of displaying preview

[aridion]

locally working on a wordpress site, keep getting this error/warning instead of displaying preview, have no idea what it means or how to fix it. please help. (Wordpress version 4.7 - XAMPP version 7.0.13 - MAC OSX 10.11.6)

[Nobbie]

locally working on a wordpress site, keep getting this error/warning instead of displaying preview, have no idea what it means or how to fix it

Same for me - i even dont know WordPress. You are in the wrong forum (this is the Xampp OSX Forum, not a WordPress Forum), proceed to WordPress and ask the support. You wont get any help here.