For some reason the changelog information for a gerrit repo could not be processed properly to provide the revision number, committer name, or anything other than the fact that there was a change.
These changes get output to the changelog.xml file with nothing but the paths and the committext. When the changelog is processed, the committer name is given as "unknown" with the given domain default.
Because email@example.com is not a valid address, no email is sent out. Even when there are many more valid email addresses to send the notification to.
I saw where this same type of invalid email address issue was resolved for
JENKINS-9006, but we are still experiencing it being rejected with our secured LDAP authentication.