There is a Privacy settings in the iOS Settings app which user can control a permission for AwesomeCalendar to access iOS calendar database, photo library, contacts, reminders and location service from another application.
So if user do not give a permission to AwesomeCalendar, it cannot display or create a event at all. Check your Privacy settings in iPhone Settings.
Note: In spite of giving a permission, if the AwesomeCalendar does not work properly, remove the AwesomeCalendar from App switcher and restart the AwesomeCalendar. Make sure that you do not need to reinstall the app, just start over it.