09.09.2026
Why can't I book this?
Opening hours, deadlines, limits – why a booking fails
Behind every refused booking sits a rule of the unit: opening hours, closing days, maximum duration, lead times or a limit on bookings. The rules in force can be looked up on the resource. On top of that comes the collision check, which also covers dependent resources.
Zeitwart does not allow every booking. Behind the refusals are rules your organisation sets per unit – and you can look at them before you try.
Looking at the rules
Open the detail view of a resource. There you can have the booking rules shown. What you see applies to that room, inherited from the unit it belongs to.
What can be governed
Rule | Effect |
|---|---|
Opening hours | outside them nothing can be booked; the times are listed per weekday |
Closing days | individual days when nothing works at all – public holidays, shutdowns |
Maximum booking duration | how long a single appointment may last |
Minimum lead time | how short notice you may still book at |
Lead time | how far ahead you may book – often a few weeks |
Maximum bookings per day or week | how many appointments you may create in that period |
Booking limit per day or week | how many hours in total you may occupy |
Maximum resources | how many rooms one booking may contain |
Not every rule is active everywhere. What is not switched on does not appear in the overview either.
Inheritance
Units sit in a hierarchy. A unit inherits the rules of the one above it but can override them. The rule overview therefore states which unit a rule was defined in.
That explains why two rooms in the same building can have different rules.
The collision check
Independently of the rules, Zeitwart checks whether appointments get in each other's way. This is not limited to the same room: divisible rooms, dependent resources and items needed in several places can block one another.
That is why a resource can be occupied although its own calendar looks empty – what is occupied is the room it was divided from.
The most common refusals
What you see | What is behind it |
|---|---|
"No booking is possible on this day" | a closing day, or outside opening hours |
The period will not save | the maximum booking duration is exceeded, or the minimum lead time is undercut |
The day you want is too far ahead | the permitted lead time is shorter than your intended date |
Nothing more works today | your limit of bookings or hours for the day is reached |
The resource is occupied but the calendar is empty | a collision through a dependent or divisible resource |
When a rule is in the way
Rules are set deliberately and cannot be worked around. What helps:
Move. The filter shows you, with "Free on … from … for …", the resources that actually fit your period.
Request instead of book. With resources that require approval, a human decides – see Approving bookings.
Ask. Whether you really need the rule in that form is a conversation with your administration, not a technical problem.