Errors in multiple plugins after migration to root

Hi, I recently moved a wordpress site from a subdomain to the root. Everything works fine, except for some plugins. I get a lot of Syntax and Type errors in Safari Console. All the errors happen in the WP-admin section. The front-end looks good.

For example: I can’t use the back-end editor from Visual composer anymore. Not a single form from Ninja-Forms loads in the front end. The build in contact form from my theme doesn’t submit (404).

I’m not very familiar with code and such, but after some googling I think it might have something to do with the file permissions on the root folder.

I hope some of you guys can help me out.

Thanks a lot!

Kind regards,

Mats