How can I enable debug logging of the notification system in Jira Service Desk?

[Daniel Varela Santoalla]

I am seeing that only one particular user, in one particular ticket, in one particular project is not receiving notifications about comments. If I clone the ticket, keeping attachments and links, notifications work fine, so it cannot be related to user or project configuration...

Would be good if I knew for which package to enable debug so that I can try to get something extra from the logs