Coursepress. Sorry, you are not allowed to access this page.

I got this message in my dashboard after installing CoursePress Pro:It looks like you had CoursePress 1 installed. In order to upgrade your course data to CoursePress 2, we strongly recommend you to backup your website before upgrading here. Once the upgrade is complete you will be able to use CoursePress again.

When I press HERE button i get this error: 
Sorry, you are not allowed to access this page.

I try plugin/theme conflict - no results.
I try to change php version - no results.

This part repeats all the time in debug:

[12-Feb-2018 14:30:31 UTC] PHP Notice: Trying to get property of non-object in /***/public_html/wp-includes/nav-menu.php on line 780
[12-Feb-2018 14:30:31 UTC] PHP Notice: Trying to get property of non-object in /***/public_html/wp-includes/nav-menu.php on line 784