Calendar troubleshooting
The messages you can meet in Calendar, what they mean and how to fix them.
Messages and fixes
| Message | What it means | What to do |
|---|---|---|
| 'The event ends before it starts.' | The end is the same as or before the start. | Set an end after the start. |
| 'An event lasts at most 60 days; repeat it instead.' | An event is longer than 60 days. | Shorten it, or use a repeating event. |
| 'You only read this calendar.' | You are only a viewer of the shared calendar. | Ask a calendar administrator to make you an editor, or use My Calendar. |
| 'Only the organiser or the calendar's editors change this event.' | You are an attendee, not the organiser or an editor. | Answer with Going?, or ask the organiser. |
| 'You are not invited to this event.' | You tried to answer an event you are not on. | Ask the organiser to invite you. |
| 'Conference Room A is already booked 2026-10-06 10:00 to 11:00 for “Client Meeting”.' | The room has an overlapping booking. | Choose another time or room. Times that only touch do not clash. |
| '<name> is not bookable now.' | The resource has Bookable switched off. | Ask an administrator to switch it on, or choose another. |
| 'An online link starts with https://.' | The meeting link does not start with the protocol. | Paste the full address. |
| 'Enter a valid e-mail address.' | A guest or customer e-mail is badly formed. | Correct the address. |
| 'At most five reminders.' | An event can hold five reminders. | Remove one. |
| 'A colleague attendee must belong to this company.' | An attendee is from another company. | Invite them as a guest by e-mail. |
| 'From the first occurrence, change the whole series.' | This and following events is not offered on the first occurrence. | Choose All events. |
| 'Choose the first to fourth, or the last, weekday.' | Monthly on the same weekday cannot start on the 29th to 31st. | Choose on the same day, or start earlier in the month. |
| 'End after a number of times or on a date, not both.' | A repeat has both a count and an end date. | Keep one. |
| 'Name who takes these appointments before publishing.' | A public appointment type has no staff. | Choose staff in Who takes these. |
| 'Two windows of one day overlap.' | Opening hours overlap. | Rewrite the windows, for example 09:00-12:00, 13:00-17:00. |
| 'Use a time as HH:MM.' | A time is not in two-digit format. | Type 09:00, not 9. |
| 'The working day ends before it starts.' | Settings have an end before a start. | Correct the times. |
| 'That time is no longer available. Choose another slot.' | Someone booked the slot first, or notice passed. | Choose another time. |
| 'You already have three bookings of this kind coming up.' | A customer's e-mail has three upcoming bookings of a type. | Cancel one first. |
| 'It can be cancelled online up to 24 hours before it starts; please call us.' | The customer's cancel notice has passed. | Staff cancel it from Appointments. |
| 'It has not started yet.' | Done or no-show is for started appointments. | Wait until it starts. |
| 'This appointment type is closed.' | The type is inactive. | Ask an administrator to reactivate it. |
| 'The Calendar app is not installed for this company.' | The app is switched off. | Ask the administrator to turn it on. |
| 'Creating a shared calendar needs the calendar.manage permission.' | Your role lacks the right. | Ask a calendar administrator. |
| 'This record changed since you opened it. Reload it and try again.' | Someone saved the record before you. | Reload and redo the change. |
| 'Event not found.' | The event does not exist, is in another company, or is in a calendar you cannot read. | Check the calendar membership. |