Fatal Error - call to undefined function - Avada

I have just reinstalled my new license for Avada Theme Fusion.
Now I cannot make any edit to my home page. I receive this notice:
Fatal error : Uncaught Error: Call to undefined function wp_check_post_lock() in /home/customer/www/whitedoveceremonies.com.au/public_html/wp-content/themes/Avada/includes/lib/inc/fusion-app/class-fusion-app.php:2355 Stack trace: #0
Can someone please assist in removing this error.
Also I am new to this forum. Is this the best way to seek support?

Replace define( ‘WP_DEBUG’, true ); to define( ‘WP_DEBUG’, false ); on wp-config.php file and and report errors to your Avada Support.


Please contact the author of your purchased theme, the author will assist you.

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