Well, While importing the demo content you didn’t install contact form 7 plugin. For that reason, you are getting Invalid Post Type mc4mp-form error. Regarding the below issue for instagram, its pointing the plugin issue which folder name is differ-widgets. so please disable that plugin and try it once.
Info:- to make your database clean please use WordPress Reset Plugin and reset your database.
Let us know if you need more help please do reply.
I would like to ask you a favor hathehuy. Would you mind taking a few minutes to write a review for me, please? Your comments help others know what to expect when they’re looking for the theme we offer.
Link to rate our theme: https://wordpress.org/support/theme/yugen/reviews/?filter=5
Thanks for using our theme, hathehuy. I’m looking forward to reading your comments.