Definition

When you are logged out of JIRA and access an URL from a saved filter (received from an email for example), it will bring you to a page with an error The requested filter doesn't exist or is private. Try logging in.

Suggestion

It would be better if you will be directed to the login page instead of the warning message. There's a Knowledge base article published to force JIRA to direct the users to the login page but it's no longer working in a newer JIRA versions (tested on 7.2.3, 7.4 and 7.5)