Cannot login to JIRA when URL Contains an Underscore in Internet Explorer

Symptoms

When logging into JIRA through Internet Explorer with a URL that includes underscore (http://mycompany_jira.com), it will redirect every login attempt back to the login page. Logging in through through the Firefox, renders correctly.

Cause

This problem is specific to Internet Explorer. Internet Explorer is compliant with the RFC that defines the validity of an URL. An URL considered invalid in the RFC rules if the URL contains an underscore ("_"). This also could be caused by the base URL and Apache.

Resolution

1. Connect JIRA using the IP address or use "localhost" if it is on the same machine.

2. For a long term solution change the defined URL that doesn't contains an underscore.