Security News > 2021 > May > Microsoft: Office 365 is blocking emails from Google, LinkedIn domains

Microsoft is working on addressing an Office 365 issue that has resulted in legitimate emails sent from multiple domains getting tagged as malicious and quarantined.
"Users having multiple issues related to email flow, links within email messages and the Microsoft Defender portal," Microsoft says in the Microsoft 365 admin center.
Microsoft says the issue stems from an accidental block placed on valid and healthy domains, which resulted in legitimated emails inadvertently being quarantined.
"We're working to release the email messages that were quarantined, as well as investigating options to restore the health of the Microsoft Defender portal."
Update 1: Microsoft has fixed the bug that led to legitimate emails getting quarantine and is working on releasing messages already quarantined by mistake.
Update 2: Microsoft processed all mistakenly quarantined emails and is now unblocking users still unable to send new messages.
News URL
Related news
- Microsoft blocks ActiveX by default in Microsoft 365, Office 2024 (source)
- Microsoft: Office 2016 and Office 2019 reach end of support in October (source)
- Phishers Exploit Google Sites and DKIM Replay to Send Signed Emails, Steal Credentials (source)
- Microsoft fixes machine learning bug flagging Adobe emails as spam (source)
- Microsoft fixes Exchange Online bug flagging Gmail emails as spam (source)
- Microsoft will update Office apps on Windows 10 until 2028 (source)