Microsoft experienced a nationwide outage in the US last week over a two-day period.

Last Monday the company’s instant messaging service Lync – part of its cloud service Office 365 - experienced technical issues in North America with users reporting connection problems from 11am ET.

Lync combines VOIP (voice over IP), corporate instant messaging, presence, meetings, screen sharing and video conferencing.

At 12.22pm ET Microsoft’s Office 365 Twitter posted: “We realize some Lync users in North America are experiencing issues, we are working to resolve. Please check SHD for status.”

Microsoft’s Lync account announced at 3.30pm ET that “some Lync users in North America are experiencing issues, we are working to resolve”.

Technology news site ZDnet spoke to Microsoft regarding the Lync outage and was told the outage was due to network routing infrastructure issues.

"Some users in North America are experiencing issues with Lync Online due to network routing infrastructure issues. In response, engineers have routed a portion of network traffic to an alternate data center which has restored service for some of our customers. We are committed to fixing this issue as quickly as possible and expect the service to be restored for all customers soon. Customers can get the latest Lync Online status through the admin Service Health Dashboard," a Microsoft spokesperson said.

The very next day Microsoft experienced another outage but with its email service Exchange online which affected approximately 50 million people across the US.

Many users of the service were unable to send or receive emails for most of the day.

Phoenix-based news station CBS5 AZ reported the Exchange outage and said they were victims of it too.

Data Doctors founder and CEO Ken Colburn said email has become a fundamental way for businesses to communicate.

“Losing email is now like losing your wallet and keys,” Colburn said.

“A lot of businesses are unable to use their email, their contact lists or get to documents. It’s a pretty massive outage.”

One user said she hadn't had access to email for 24 hours.