tour schedule

Hi everybody,

i have an issue with my tours schedule since 2 weeks i can’t solve it. When i tap on Schedule from the Tour menu it appears a blank page.
The curious thing is that if i get t my wp-admin as author, not administrator, i can see the schedule page without problems. Does someone can help me please?
Thank for each kind reply

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