We recently installed Jira behind a proxy (Apache). Jira was accessible via https://subsubdomain.subdomain.domain.com/jira/ however after logging in users were forwarded to https://subsubdomain.subdomain.domain.com/jiraLOGIN_PAGE_JIRA
(note the missing "/" after "/jira"). The proxy couldn't recognize that path and therefore threw a 404, however if users manually added the missing slash everything worked like a charm.
So we thought we forgot to configure "/" in the base-url and it really wasn't there when we looked into the settings through the admin page in the frontend. Naturally, we tried to change it and discovered that Jira simply did not accept our base-url ending with a slash. It seemed like the frontend's Java-Script just removed it (Note changing the base-url to "https://subsubdomain.subdomain.domain.com/jira/ABC" worked fine). So typing in a path ending in [...]ABC/ results in the base-url [...]ABC being saved without any notice to the user that slash was removed or something.
Until now we are not sure if this is a bug or a feature.
So would be nice to know if other folks encountered this "problem" and also would be great if someone from Atlassian could comment if this is a desired behavior or a bug.
If anyone really has this problem the fix is:
just add another proxy rule that forwards
https://subsubdomain.subdomain.domain.com/jira (Note: no slash at the end here) to the same backend as your old rule for https://subsubdomain.subdomain.domain.com/jira/ does.
So a simple copy and paste and removal of one slash followed by a restart of your Apache proxy solves the problem.
Any information on this topic is greatly appreciated.