Many users have complained of the inability to send out messages with email service Microsoft Outlook.
The company has also admitted there has been a fault which is being looked at.
Microsoft Outlook users headed on to website Downdetector to issue complaints about the disruption of their mail service. It is being reported that not all account holders were affected by the bug.
A common complaint circulating among users is that sent mails end up in draft folders instead of going to intended recipients.
In seeking out an interim solution, the company has provided an “alternate infrastructure” for its customers.
“We’ve identified that a subset of infrastructure was unable to process requests as expected, which caused general service availability to drop unexpectedly,” it says.
“We’ve redirected requests to alternate infrastructure to restore service, and we’re monitoring the environment while connectivity recovers.
“Additionally, we’re investigating an issue in which users are unable to send email messages.”
Outlook is a free email service offered by Microsoft, formerly known as Hotmail and Windows Live Hotmail, both accounts which have since been incorporated into Outlook.