GitLab EE users not receiving email notifications - jrcloudsolutions/tidbits GitHub Wiki

When the Kubernetes Worker Nodes were drained to increase the amount of memory and CPUs, they obtained a new IP address and were unable to send email notifications to GitLab users, i.e. when a new user was created or when a new merge request was created

Resolution: I contacted the firewall team to whitelist the entire subnet where the Worker Nodes resided.