Outlook vraagt om wachtwoord zonder dialoog venster

Dit is een bug in Windows/Office en heb het al een paar keer gezien. De volgende website beschrijft goed welke opties je kunt proberen:
https://superuser.com/questions/1349327/outlook-needs-password-but-dialog-box-disappears

A collection of various known Outlook fixes for login problems :

• Run Credential Manager, and if your account is listed ensure that it’s correct.
  • If not correct, fix it.
  • If correct, try deleting it, reboot and log into Outlook.
• Logging-in into Web Outlook might sometimes show an existing problem such as the need to change the password.
• Start Outlook in safe mode by running Outlook.exe /safe and enter the ids if asked.
• Unlink the Microsoft Account from Outlook
• Disable Modern Authentication by regedit to HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity, create a DWORD item named EnableADAL and set it to zero.
• Under the same registry key, create a DWORD item named DisableADALatopWAMOverride and set it to 1. See Microsoft article.