While Outlook is running, click the CTRL key and then right-click the Outlook icon in the system tray, select “ Test Email Autoconfiguration”.ī. What's the detailed version of Outlook 2016? You can check it via File > Office Account > About Outlook.īesides, it's suggested to run the ' Test Email Autoconfiguration' when the issue occurs to see if any clues can be found:Ī.What's the version of your Exchange server? Which CU build is it?.When the prompt appears, can Outlook continue to work as usual if you enter the credential required? Or do you mean the prompt just keeps popping up?.Does the issue only occur to a particular user? Or all users are affected?.From the 2nd link you shared above, seems like you have already tried adding the registry key 'ExcludeExplicitO365Endpoint' with no luck, right? If this is the case, could you provide the following information so that we can understand better about the situation?
