Regards. Mail from a university, for example [email protected] does not reach my server's mailbox, but gmail does. The server works fine, I receive emails from other sites and everything is normal. I have the following message in the mail.log: If I enter mail.university.ar.ra if a website is displayed in the browser If I enter mail.domainuniversity.com a website is not displayed in the browser So it is possible that the mail.domainuniversity.com is not configured correctly, that's why my server does not receive it, but gmail does. What I have tried for tests according to the manual and it does not work: Add the email address and the two websites to the postfix whitelist in global filters and ispconfig spam filter In Domain and Mailbox I select the spam filter: Unsensored. The questions are: How can I get emails from this site? How could I allow emails from sites with the .ar.ra domain that are from universities and the government? Sorry for the questions and thank you very much for the help.