Use email address from Git commit to send Jenkins notifications

I installed the Jenkins task with the Git plugin and now I want to use the email-ext plugin to send failure notifications to the email address specified in the interrupt. But then I always get

"An attempt to send an e-mail to empty list of recipients, ignored"

therefore, it seems that email addresses are not retrieved. I don't want to create separate user accounts for everyone, if possible, and even if I do, how do I link them to a Git commit? (the option "Create a new database of accounts on the author / committer’s email" will probably scan all previous commits that the wrong users may create, because some people have incorrectly configured the email address, so I only want it for new commits)

Does anyone have a working setup with the email plugin?