WPBakery backend editor not showing after installed several WPMU DEV plugins

Hi Support Team,

After I installed several WPMU DEV plugins I found I cannot access to the backend editor of WPBakery (https://imgur.com/j37VYmj).
I tried deactivating the plugins and found the problem comes from SmartCrawl. Every time I activate SmartCrawl, the backend editor will not be showing.
Is there any way to solve this problem? Thanks!
* What the page looks like after deactivating SmartCrawl: https://imgur.com/Nau7ts4