Timeslot Booking Failure - Incorrect 'Unavailable timeslot' Error

[johnathan-booy]

Issue Summary

Starting today, our users began experiencing an issue with booking available timeslots. After selecting an available timeslot, users are initially presented with the booking form where they can enter details. However, upon attempting to confirm, the "Confirm" button is disabled, and the following notification appears:

Unavailable timeslot The selected time slot is no longer available. Please select a new time.

This issue is consistent across all team members and multiple event types. It occurs on both embedded booking pages and direct Cal.com booking links. Additionally, the issue affects two separate Cal.com teams we maintain (production and staging), which are completely isolated environments.

Refreshing the booking page temporarily resolves the issue, allowing users to proceed with booking. This issue appears to have started following the release of v5.0.19 today.

Steps to Reproduce

1. Open a booking page (embedded or Cal.com direct link) in a new incognito window
2. Select an available timeslot.
3. Notice the confirm button becomes disabled.

Observe the notification stating the selected timeslot is unavailable.

Actual Results

• After selecting an available timeslot and attempting to confirm, users see an error message incorrectly stating the timeslot is unavailable.
• The "Confirm" button is disabled, preventing completion of the booking.

Technical details

• Occurs on multiple browsers (Chrome, Firefox, Safari).
• Issue affects embedded and direct Cal.com booking links.
• Occurred immediately after the Cal.com v5.0.19 release.

Evidence

• Tested extensively across production and staging teams, multiple users, and various event types.
• Confirmed issue through repeated attempts; reproducible consistently.

[mattpweiler]

I am experiencing the same issue as well. The error is only in my embedded calendar and not when I visit the link in a separate window or tab

[capitaineohe]

I am experiencing the same issue but only on embed booking page.

When I click to book a slot, I get a message telling me that the slot is no longer available. I go back to choose another slot and it starts all over again.

Then the slots are no longer available in the calendar, even though no reservation has been made (cache issue ?). I Have to run troubleshooter to refresh availabilities.

[parteekmalik]

This might be related to #20064. Is this the issue?

[parteekmalik]

@capitaineohe if this is not the issue. Can you share some details look?

[mattpweiler]

This issue should be resolved now. It was a known bug with one of the releases last week

[TusharBhatt1]

Thanks for raising , the issue seems to be fixed : https://github.com/user-attachments/assets/e85e3eee-2192-42ee-910f-de168b7d03aa