timjrye

That’s understandable! No worries. In the meantime I have just deactivated the plugin on all my sites.

Any update on this?

Yes, sorry I should have done that before! The score is 9/10. We lose one point because the message is not signed with DKIM.

I should also have mentioned that I can send test emails fine, they arrive correctly in my inbox, and I checked our newsletter on mail-tester.com and the results were ok.

Running phpinfo() shows that the memory limit is already 128M. I have increased it to 256M and the plugin now works fine.

Is there any negative effect of setting the memory limit so high?