Where are error logs stored, specifically those logs pertaining to notifications?

[Luciano Fagundes]

If you're having problems with notifications, you can run the JIRA Notification Helper to help you troubleshoot what's wrong. For that please refer the URL below.

https://confluence.atlassian.com/display/JIRACLOUD/JIRA+Admin+Helper#JIRAAdminHelper-NotificationHelper

If you want to take a look on the application logs, you should open a request on http://support.atlassian.com to request the log files.

Hope it helps! 

Cheers

L.F

[Jaime S]

As Luciano said, you have to contact Support. Also, email logs are not enabled by default, so we may need to enabled then and replicate the problem to have data.