Js errors in wp-admin

I’ve seen something similar to this but your situation may be different. In my particular situation, the server did not have enough resources to use Visual Composer and support all the visitors on the site. Try to make your updates at a time when you have the least amount of active visitors and you might have more luck. You can also reach out to your hosting company and ask if you are maxing out your server resources. If your hosting company gives you access to cpanel or something similar, you might be able to look this up on your own. Good Luck!