Hi ! Time to time I have problem sending mail from ISPConfig 3 (setup on Debian from Howtoforge) - "host not found mail.protection.outlook.com" in log file. It is also described here https://techcommunity.microsoft.com...-found-mail-protection-outlook-com/m-p/203226 and here: https://www.howtoforge.com/communit...ix-cannot-send-emails-to-some-accounts.82423/ Unfortunately, author of the last post did not shared his solution. How to fix this? Thanks in advance.