Still Unable to Update from 1.7.10

Previous support thread on this topic never received a further reply:

https://wordpress.org/support/topic/fatal-error-memory-exhaustion-with-gravity-forms-and-latest-version-of-postman/

When using any version of Post SMTP higher than 1.7.10, the plugin malfunctions in multiple ways:

-The email log will not show, only a blank page when you click “Email Log.”
-A test email will appear to fail, showing “Ajax Error,” but the email will come through. This happens even with all other plugins disabled.
-Sending emails through Gravity Forms (the main component of the WordPress site in question), only the first email in a set will be delivered. If it tries to send more than one notification email, anything after that will fail.

When rolling the plugin files back to 1.7.10, the issue disappears. All emails can be sent normally and “Test Email” shows no error even with all other plugins enabled.