I have the same issue. I probably didn't configure the JSD project correctly, but maybe someone could help me with it?

The scenario I imagine:

1. Customer loggs a ticket
2. Agent shares the ticket with a person not yet having a JIRA account.
3. Person without JIRA account receives email that the request has been shared with her or him.
4. Person without JIRA accoun uses the url from the email, creates account and views/updates the ticket etc.

I got up to point 3 and everything works, but on point 4 I get the "oops" page. Can anyone shed some more light how this should be set up? And also, once you share a request, where should it be visible on the request that there is a participant? I am able to add a person, but than see no sigh on the ticket of someone additionally added as Participant.

IF you have issue security enabled, you only have to add Service Desk Customer - Portal Access (Project role).
Now the participant is able to access the issue (via the portal).

jacek.pietsch, what problems are you having with request participants? They are not getting notifications on comments and status updates? If they can access the requests where they are participants on the Customer Portal, then it's probably not caused by the issue-level security settings. I'd suggest that you open a support ticket so that our support team can help you out: https://support.atlassian.com/servicedesk/customer/portals

Documentation on issue-level security can be found here: https://confluence.atlassian.com/display/Cloud/Configuring+Issue-level+Security.

Can you please explain in more details how to correct this Issue Level Security schema?
I want "Request participants" to be able receive comment's notifications and status updates.

Good to hear ben.bowen!

Success! It was the Issue Level Security, as you indicate. This was not so clear from the documentation. Thanks for you assistance. This ticket can be closed.

Hi Ben,

I have managed to reproduce your problem by applying issue-level security to the issue, restricting it to only be viewable by the reporter. Request participants does not bypass issue-level security, however the fact that the users appear as people involved may be a bit confusing.
If your case is different and your participants are still not able to view requests, please create a support request at https://support.atlassian.com/servicedesk/customer/portal/3 (I believe you should be able to login using the same username and password as here).
Thanks for providing the detailed description and screenshots .

Regards,
Oliver Wessels
JIRA Service Desk Team