Starting at 8 January 2024 several regions of Microsoft's outlook.com mail services are listed on the famouse RBL spamcop. Here the details: https://answers.microsoft.com/en-us/msoffice/forum/all/microsoft-365-mailserver-blacklisted-by-spam-cop/087975ef-c93e-417a-b2c6-31315d63c53d This mean that this blacklist spamcop, does not allow the ...