Open control panel mail – you can use the /manageprofiles switch to open it – right-click on the Start button and choose Run or press Windows key + R to open the Run command.
Type or paste the following into the Open field and press Enter or click OK to restart Outlook. (There is a space before /.)
outlook.exe /manageprofiles
Cannot add email account to Outlook 2019 where the username is not the email address
