An user report not able to connect to Github and getting the following error message:

"Invalid user/team account"

After do some testing, it seem the DVCS Connector Plugin version is not compatible with JIRA 6.

Finding:

• User has small instance.
• JIRA 6 running DVCS Connector Plugin version 1.3.1.

Workaround:

• Install the latest DVCS Connector Plugin version via https://marketplace.atlassian.com/plugins/com.atlassian.jira.plugins.jira-bitbucket-connector-plugin