EX186942 - Outlook client connectivity issues in specific scenarios
Outlook client connectivity issues in specific scenarios User Impact: Users with multiple enterprise sign-in accounts can't connect to Exchange Online via the Outlook desktop client. More info: Further investigation shows that this issue is specific to users with multiple related and trusted Enterprise log-in accounts across Microsoft 365 and Windows. If you have users experiencing issues connecting to the service or impact outside of what is described, please submit a ticket with support. Users experiencing this problem will see the Outlook desktop client showing as disconnected and may receive the following error when attempting to send mail: "Sending and receiving reported error (0x80040115). The connection to the Microsoft Exchange Server is unavailable. Outlook must be online or connected to complete this action." Users may be able to leverage one of the following options to circumvent impact for this event: - Affected users may be able to use Outlook on the web or mobile clients to access their mailboxes. - Additionally, users may be able to restore access by forcing new authentication to all office apps as noted below: 1) Close Outlook and other Office applications. 2) Open an Office desktop application, such as Word, PowerPoint or Excel. 3) Navigate to File > Account > Switch accounts, and then click the ellipsis next to the account that's not having the problem. 4) Click Sign out and then OK. *Note: Users that have multiple accounts may find it difficult to determine which account to sign out of; though, they should be able to sign back in later if there is an issue with this process. 5) Close the Office application used for this process and re-start the Outlook desktop client. 6) When prompted for a password, click "sign in to a different account" and enter the correct information. - Lastly, affected users may be able to restore access by creating a new Outlook profile, further instructions can be found via the following link.