OJS email problems

We’re having multiple email problems on our instance of OJS.

We get SPF authentication failures on Gmail as well as some other domains. Further, in some of our journals (but not all), editors do not receive the initial email notification that a new article has been submitted. Additionally, emails sometimes do not send if the author and the journal editor are from the same institution.

After consulting the docs, we created a new email address following SPF protocol and added that address as the envelope sender. We’re still having no luck solving the above problems, however. Any advice would be appreciated. Thanks. We’re using