“The issue was caused by a high volume of SPAM messages being sent to Windows Live accounts which triggered Microsoft’s anti-spam software to block some emails, Microsoft has since liaised with the NHS to implement new anti-spam and anti-virus systems which will prevent this from happening again,” said a Microsoft spokesman.

A spokeswoman from the Department of Health said, “As soon as NHS Connecting for Health (NHS CFH) became aware of the issue, immediate steps were taken to rectify the matter.”

Source: The Register