Please test now, I made some changes in "components\com_guru\controllers\guruLogin.php" file. All these changes will be added in the next version too. Now, after login, the "Registered" user is redirected to cart page, because the course is free only for "Manager" users.
We've been testing access to the courses for some time so far and it worked well for the first few days, but after a while the problem reoccurred. In order to get access to courses, it is necessary to remove all the cookies (which shouldn;t be the case, cause regular Internet users don't know about it).
Please have a look at it once again.
I just made a test, I was logged with a registered user and when I open a course I can directly enroll to that course, the course is free for registered users. If I am not logged, I click on lesson, the registered modal page was opened and after login with registered user I was directly enrolled to that course.
Please let me know what is the real issue.
The real issue occurs after a few days of correct functioning of the system. After you introduced your changes, it worked for a few days. After that we had to remove all the cookies to enable registered users to use the courses once again. Any registered user who has been using a course for a few days who clicks Enroll and logs in is redirected to the basket page instead of having a direct access to the course. Once we've removed all the cookies, everything works fine once again.