Outlook Add-in asks credential after OS reboot

Hi All,
I am using NC 16.0.4 on Raspbian Stretch with Outlook Add-in 2.3.1.17.
I scheduled a restart of the raspberry twice a week, and after each restart when I open Outlook the add-in asks me to re-enter the credentials (username and app password).
Has anyone ever had the same problem?
Thank you so much for your help.
Best Regards,
Omar