GitLab - Changing default system emails

I have setup GitLab but having issues with changing the default email. It keeps using the external URL as the sending email address. For example, the external URL is set to domain.local in the /etc/gitlab/gitlab.rb file and GitLab keeps sending the email from gitlab@domain.local instead of the gitlab@domain.com.

I have already configured Postfix to send as the .com domain and system emails are coming out as root@domain.com. However, GitLab seems to be appending the external URL as the from email instead of whatever I have configured in the Postfix configuration file.

Is there a way to fix this problem? Thanks.