ISPmanager does not send mail
Advice on setting up sending mail by scripts in the ISPmanager control panel
If you have ISPmanager, you need to add your VPS email into site settings for correct emailing by scripts.
To do this, create a mailbox (if you haven't created it yet) and specify it as E-mail of site administrator in the site settings.
Everything! Mail should work without problems.
Read more information about setting up mailboxes in ISPmanager5 [here] (https://fornex.com/help/mail-isp5/).