According the report, when affected users attempt to update their operating system, Windows displayed the following error report:
We couldn't connect to the update service. We'll try again later, or you can check now. If it still doesn't work, make sure you're connected to the Internet.
It is unclear what caused this issue, with many users speculating that it was either a problem with Windows Defender or their DNS configuration.
This problem does not affect all Windows 10 users, but a number of users who were affected by the issue have stated that switching their DNS allowed them to download updates.
Microsoft said the issue has been fixed, but if you are still unable to download Windows updates, switching to Google's public DNS service may resolve the problem.
