[Solved] GitLab 8.9: panic: runtime error: invalid memory address or nil pointer dereference

There's a known issue in GitLab 8.9 where error messages aren't pulling properly from localization files and Mattermost issues a "panic" message.

A common cause is attempting to automate SMTP email setup with configuration information would throw an error.

To address this:

1. Set mattermost['email_send_email_notifications'] = false in /etc/gitlab/gitlab.rb and run reconfigure
2. After the Mattermost server starts go to System Console > Notifications > Email to enter your SMTP information and click "Test Connection" to find the error and setup SMTP.

The fix for the error in log messages is already on master and will be released with Mattermost 3.2 on July 16.