Build plan branches do not send email notifications

I have a Git repository configured in Bamboo 4.0.1, and I'm trying to use Branch Notifications. My Mail Server is correctly configured.
My Git master branch is listed under 'Branches' section of the Plan, and this is written in the Bamboo user interface under Branch Notifications:

Notifications for your branch will be automatically generated. All committers and all people who have favourited this branch will receive notifications for build failures and first success after failure.

If the notifications will be sent automatically, no notification rules need to be configured in Plan Configuration > Notifications tab.

I have a Git Author defined this way:

git config --global user.name "Administrator"
git config --global user.email fkraemer@atlassian.com

This user exists in Bamboo, with these details:

• User Name: administrator
• Full Name: Administrator
• E-mail: fkraemer@atlassian.com
• Source Repository Alias: I tried to use three different aliases: administrator, Administrator, and Administrator <fkraemer@atlassian.com>
  This third one I retrieved by running this command in my Git repository: git log --raw | grep "^Author: " | sort | uniq -c

I committed code into master branch using this author and run a build, but I wasn't notified.
I also tried to add this plan as favorite to the administrator user, commit again and run a build again, but I wasn't notified as well.