The relationships of these standards to OJS is discussed a bit here: What version did you upgrade from?
Otherwise, there have been a couple of recent changes to the way email is sent. == Begin Technical Excursion If you upgraded from a version before 2.4.6, email was sent directly "from" the email address specified by the sender's profile in OJS to the email address specified in the recipient's profile. The best way to troubleshoot email problems is digging into the SMTP logs (which you may not have easy access to) and the SMTP headers (which are hidden within every email you receive).
Please, explain this situation, maybe we missed some important step.
Regards, Sergey Morenov, Samara University What version did you upgrade from?
@asmecher's suggestion is a good start for seeing if other mail sent natively from the server gets delivered.