SysAdmin
It started off with an employee sending an email to a distribution list called "Bedlam DL3" asking to be taken off the list. With 13,000 recipients and everyone replying all with, "Me too!" and other messages, it was estimated that over **15 million** messages were sent through the system in an hour. This crashed the MTA service due to a recipient limit. Each time the MTA service recovered, it would attempt to resend the message again which lead to a crash loop. As a result of the incident, the Exchange team introduced message recipient limits and distribution list restrictions to Exchange, which is something we all use today! More on the story here: [https://techcommunity.microsoft.com/t5/exchange-team-blog/me-too/ba-p/610643](https://techcommunity.microsoft.com/t5/exchange-team-blog/me-too/ba-p/610643)
From M365 Service Health Dashboard: EX610644 Title: Some users in North America may be unable to access their Exchange Online mailbox using Outlook on the web User impact: Users in North America may be unable to access their Exchange Online mailbox using Outlook on the web. More info: Affected users may encounter an unexpected 500 error when accessing Outlook on the web.
