LINE 854 E_ERROR

I have no idea what to do with this…

Version 6.0.0 | By Vasyl Martyniuk | View details
This plugin failed to load properly and is paused during recovery mode.

An error of type E_ERROR was caused in line 854 of the file /home1/gwenslif/public_html/wp-content/plugins/advanced-access-manager/application/Migration/2019_06_30-base.php. Error message: Uncaught Error: Call to a member function setTimezone() on boolean in /home1/gwenslif/public_html/wp-content/plugins/advanced-access-manager/application/Migration/2019_06_30-base.php:854 Stack trace: #0 /home1/gwenslif/public_html/wp-content/plugins/advanced-access-manager/application/Migration/2019_06_30-base.php(235): AAM\Migration\Migration600->_convertPostObject(Array) #1 /home1/gwenslif/public_html/wp-content/plugins/advanced-access-manager/application/Migration/2019_06_30-base.php(111): AAM\Migration\Migration600->processPostmeta(Array) #2 /home1/gwenslif/public_html/wp-content/plugins/advanced-access-manager/application/Migration/2019_06_30-base.php(955): AAM\Migration\Migration600->run() #3 /home1/gwenslif/public_html/wp-content/plugins/advanced-access-manager/application/Core/Migration.php(116): include(‘/home1/gwenslif…’) #4 /home1/gwenslif/public_html/wp-content/plugins/advanced-access-manager/application/Backend/Manager.php(93): AAM_Core_Migration::executeScript(‘/home1/gwenslif…’) #5 /home1/g

The page I need help with: [log in to see the link]