
Navigate to Control Panel > Credential Manager > Windows Credentials > Remove/delete any records with the users mailbox address.Option 2: Manually Update/Add the mailbox credentials to Credential Manager & re-build the Autodiscover.xml file Note: you may be prompted once to enter the user's credentials. Note: to perform the steps above automatically download and run the file below: Enter the name of ExcludeExplicitO365Endpoint and the value of 1.Note: if the Autodiscover key is missing, you can create it by making a right-click on Outlook key, select New, then select Key, and name it as AutoDiscover. Navigate to HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\AutoDiscover.Note: you can skip this step, however, we highly recommend backing up the registry before you proceed to modify its entries.

Open regedit: to do so, click the Start button and then in the Start Menu, either in the Run box or in the Search box, type regedit, and press Enter.Important: back up the registry first and be careful when making any changes to it as any incorrect action may result in the OS crash. Option 1: Edit the registry key to ExcludeExplicitO365Endpoint Try any of the options described below and contact Support if you need assistance with it. There are several workarounds that help resolve the issues.


We have identified an issue with recent builds of Outlook 2016/2019/O365. 2017 and later) /2019/O365 affected by the recent Microsoft bug (version 1809, builds 10827 and higher). Important: all workarounds described in this article apply to Outlook 2016 (version. Note: this workaround is not applicable for mailboxes hosted on Microsoft 365 accounts.
