Hello,
Thanks for using our theme and for contacting us.
Conflict with a 3rd party plugin can be the reason for the problem, or something else. We need to take a closer look.
It is recommended to run import on a fresh WordPress installation. For this you can use WordPress Database Reset plugin https://wordpress.org/plugins/wordpress-database-reset/ The plugin can be used to remove all the existing content and install a new version from scratch.
Please do the reset and reply with temporary wp-admin access here. We will help you with the import.
Create an account via Dashboard (Users > Add new) with administrator role http://prntscr.com/s3rc9m > provide us with username and password via the Private Content area http://prntscr.com/s5mao7 You can use any email for it.
Regards