Don’t know. Everything worked for me fine when I tried to adopt similar SMTP settings for my own mail server. Eventually switched to PHP mail() function, because of strange rejection of our emails to the spam folder in Google and Yahoo mails.
I would recommend setting up a test user with a gmail address on the system and generating some messages to that user. This will help you confirm that messages are being sent as expected and not being flagged as spam.
If successful, the PHP mail() function is sufficient and there is nothing additional to configure.
See this thread for more detailed information about OJS emailing and spamtrapping by Gmail and Yahoo:
The specific OJS version numbers mentioned are not as important as understanding the relationship of SPF, DMARC, and DKIM at the server level.