You may receive the pop-up that says:
|This time frame is unavailable. Please modify the time frame and try again.|
Frequently, this pop-up error occurs because you have attempted to schedule an event at a Facility outside of that Facility's Operating Hours.
You can avoid this error by either not adding a location to the event or adding a sub-facility (such as a meeting room) to the meeting's location that does not have posted hours.