We have Jira and Confluence installed on our server (Ubuntu 11.10). Programs are behind the Apache proxy in separate paths (/confluence and /jira) and configured to use HTTPS. Jira and Confluence are linked together and Confluence uses Jira's user directory. Everything works well apart the problem, that sometimes blocks the user from logging in to Jira on Confluence entirely. Instead of the login screen, user gets Unauthorized (401) error from the Jira and in Confluence HTTP Status 401 - Basic Authentication Failure - Reason: AUTHENTICATED_FAILED error from Tomcat.
We suspect that the reason for the problem is died session, that causes error instead of the login screen. Sometimes deleting cookies from the browser helps, but particularly not with Confluence.