hi,
EventOn Plugin is installed and activated on your site?
Because to show wplms eventon calendar in courses the EventOn Plugin is required
While creating course it is required to save events while connecting the course with the events
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If both the plugins actiated on your site and you have everything latest installed then do share your site URL with admin credentials to check the same at your end
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From wp-admin > LMS > Settings > Events Style > List Style
Then set the Events for course from wp-admin > Events > edit your event, add your event's start date, end date and connect the course from here
Then check in the frontend your issue will be resolved