cancellation error

User cannot cancel an event anymore, they see this message "Veranstaltung nicht gefunden - bitte zuerst anmelden!", but they are already logged in, otherwise they couldn't see the event
 

I have debugged it and got the following:

We are experiencing an issue with frontend event responses in JEM 5.0.1.
A logged-in user can view the event and select “I will not attend”. However, if the user has not previously submitted a response, saving this choice fails with COM_JEM_EVENT_ERROR_EVENT_NOT_FOUND.
The affected event is published, accessible to registered users, and has registration, cancellation and “Request answer” enabled. Its registration window is open.
Steps to reproduce:
1. Log in with a user who has no registration record for the event.
2. Open the event.
3. Select “I will not attend” and submit.
4. JEM reports “Event not found” instead of saving the negative response.
Expected behaviour: The initial negative response should be saved with status = -1 and places = 0, subject to the appropriate access and registration-window checks.
Our inspection of the installed code suggests three related causes:
- userregister() treats every negative response as cancellation of an existing registration.
- getAuthoritativeRegistrationEvents() consequently uses the owned-cancellation lookup. With no existing registration, it returns no event and triggers the error.
- Both JemRegistrationAccessPolicy::decide() and JemRegistrationQuantity::resolveResponse() also require an existing registration for negative responses.
The frontend form nevertheless offers this choice to users without an existing registration when requestanswer is enabled.
We reproduced the error in a local regression test using the original event model with simulated Joomla context and persistence. A provisional patch distinguishing initial negative responses from cancellations passes our local tests, but we would prefer an official fix rather than modifying JEM core files.
Could you confirm whether this is a known issue and whether a fix is available or planned? If an interim extension is recommended, is there a supported plugin hook for handling this case?
We have not yet confirmed whether cancellation of an already accepted registration is also affected.

Update: proposed fix successfully tested on our live siteAfter applying the attached patch, the previously failing initial “I will not attend” response now saves successfully.We tested with user ID 579 and event ID 35. Before the initial test, no registration record existed for this user/event combination. We then repeatedly switched between attending and not attending, and all attempts completed successfully.The patch distinguishes an initial negative RSVP from cancellation of an existing registration. Initial negative responses require the normal access and registration-window checks and are stored with and . Existing registrations retain their cancellation checks.The patch also passed 14 local regression tests covering access restrictions, response windows, full and partial cancellations, and quantity validation. These tests used simulated Joomla context and persistence.Could you review the patch and consider including an official fix in an upcoming JEM release? We would like to avoid maintaining changes to JEM core files.

Thank you for the detailed debugging.

You are right: this is an initial “I will not attend” response, not a cancellation of an existing registration. We reproduced the issue in our regression tests and corrected it.

JEM now saves the negative response with zero places when “Request answer” is enabled and the access and registration-window checks pass. The response remains stored as Not Attending.

Please download the refreshed JEM 5.0.2 Beta 1 from:
www.joomlaeventmanager.net/download/beta-versions

The fix is also included in the refreshed JEM 5.1.0 Beta 4.

Please test with a user who has not previously responded, then also check cancellation of an existing registration. Let us know whether both cases work correctly.

thanks for the quick update! Looks good!