Unable to add Staff to a Bookings Business

Hi! I manage a Booking page that has ~50 staff members that is used for scheduling IT support. For the last week I've been unable to add staff to the business because the hours for the staff doesn't load. Where I would normally be able to select the hours that the staff member is available it is instead blank and empty there. 
If I select use business hours and try and add the staff member I get the response - 'The meeting hours aren't correct. Please check for overlapping times or a start time that comes after an end time'. If anyone knows how to resolve this issue please let me know.