You may be an Office 365 customer who is experiencing the error that is described in the 'Symptoms' section when you try to connect to an Exchange Online mailbox. These versions have the Logon network security setting disabled or removed from the Microsoft Exchange email account settings. Those versions have been updated to prevent the problem that is described in the 'Symptoms' section. Microsoft Outlook 2016 and some recent builds of Outlook 2013 are not affected by this issue.
