Microsoft Outlook Blocking All Email from Tutanota.com as Spam Posted by toastedwedge on Tuesday December 05, 2023 @11:26AM from the tuta.com dept. https://tuta.com/blog/outlook-falsely-marks-tutanota-emails-as-junk ( 2 comments | 13 points | on HN )
Seems likely that this is in some way related to their rebrand to tuta.com.