@Tutanota Actually, I have found Outlook365 to be much, much worse than Gmail. They very often mark mails as spam, even though DMARC, SPIF, DKIM, etc. are all set up correctly. You can then, with quite some work, get them to accept the domain again - only to find it back on the spam list a few months later. With gmail, I have added the domains to the domain list in the google postmaster tool. thats it! no more gmail spam folder to my mails.