A mobile device can't connect to Exchange Online by using Exchange ActiveSync

Applies to: Exchange Online


A user's mobile device can't connect to Microsoft Exchange Online in Microsoft Office 365 through Microsoft Exchange ActiveSync. However, the mobile device previously could connect.


This issue can occur for many reasons. These include, but aren't limited to, the following:
  • The device can't connect to the Internet service provider (ISP) or to the Internet.
  • The device isn't set up correctly.
  • The Exchange Online mailbox server that supports the connection isn't available because of maintenance or an outage issue.


To fix this issue, follow these steps.The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.


Still need help? Go to Microsoft Community.