SMTP password and auth error

Hi. I have Ubuntu 16.04 LTS server, that I've just installed and Gitlab CE on it. I installed it with install-script from http://gitlab.com. Mattermost is enabled and everything works fine except SMTP notifications.

I tried to change settings from system console (in browser), but they get reset on gitlab-ctl reconfigure.

Then I tried to change directly /etc/gitlab/gitlab.rb with this settings:

mattermost['email_enable_sign_up_with_email'] = false
mattermost['email_send_email_notifications'] = true
mattermost['email_smtp_username'] = "mattermost@***.com"
mattermost['email_smtp_password'] = "***"
mattermost['email_smtp_server'] = "smtp.gmail.com"
mattermost['email_smtp_port'] = 587
mattermost['email_connection_security'] = "STARTTLS"
mattermost['email_feedback_name'] = "Mattermost"
mattermost['email_feedback_email'] = "mattermost@***.com"

They look fine when I go back to system console, but it shows me auth error:

Failed to authenticate on SMTP server [details: 535 5.7.8 Username and Password not accepted.

But now if I set password in the system console to the same password from config - everything works. Until next gitlab-ctl reconfigure when password is reset again.

So how can I set password permanently?