Not able to activate WP bakery page builder in Calla theme

I have installed calla theme and WP bakery page builder is required plugin in that and i have installed that plugin not now I am not able to activate it. Whenever I try to activate this plugin, website just shuts down and show some error.

Hi @arvindhandicrafts ,

May be there is compatibility issue with theme and/or WordPress version with the WPbakery plugin. Please contact the author of your purchased theme, the theme author will assist you.

How to contact an author to get support or for any technical query: