Unfortunately there is an issue on C1 mail server for the last 15 minutes, our devops team is working on the issue to fix it without losing any of the mails. New registration mails are still being sent successfully but other modules like SD, ITSM are not able to send emails for now.
We are very sorry for the inconvenience and all team is working on fixing the issue before the morning.
Issue is fixed now. Issue lasted for nearly 30 minutes and a portion of SD emails may have lost. Please check your ticket lists just in case a new ticket may have been created during this period and you did not receive the notification mail about it.