If an email to your Hotmail address never turned up last week, Microsoft may have turned it away

The invoice that never came. The appointment confirmation you had to chase. The password reset link you requested three times. If any of that happened to an Outlook.com, Hotmail or Live address in the first part of November, it may not have been the sender's fault, or yours.

Microsoft has confirmed that an update to its spam rules wrongly blocked legitimate email to its consumer addresses. "We've resolved an issue that may have prevented some email messages from reaching Outlook.com, Hotmail and Live addresses," the company said, and it has rolled the change back. Expert Insights reports that administrators began seeing bounces around 4 November, and Windows Latest found rejections from at least 5 November until mail flow was restored on the morning of 9 November. Senders were told their "Message lacks SPF/DKIM/DMARC Auth Records", a reference to the email authentication settings organisations publish for their domains. The block fell mostly on smaller businesses whose domains had no DMARC record, though some with everything set up correctly were turned away too.

The awkward part is that these messages weren't filtered, they were refused. They never reached your mailbox, so they aren't sitting in Junk, searching Outlook won't find them, and Microsoft can't bring them back. You don't need to change any settings. What you can do is think back over that week for anything you expected and didn't get, a delivery notice, a bill, a reply from the surgery or your child's school, and ask for it again. A person who got a bounce may already have tried again. An automated system often won't.

This one happened entirely on Microsoft's servers, so there's nothing to fix on your PC; if mail stops arriving another time and Microsoft reports no problem, Tendvane's network repair wizard is a quick way to rule out your own connection.