I have a problem (which is now fixed) but the cause is leaving me somewhat stumped…

I am looking to see what may have caused email delivery issues with a site using the following plugins WooCommerce, Gravity Forms and Easy WP SMTP.

It seems emails were successfully sent through WooCommerce but not via Gravity Forms to the client’s email address.

During the launch of the site (late 2020) I initially BCC’d myself into the emails and received copies (so we know the site ‘sent’ the emails sent successfully) – but the client claims these emails were never received (but the WooCommerce ones were)

I do now have all the emails being received successfully – which was done by one (or two or all) in the following ways

1. Added a DMARC record to the domain
2. Updated all plugins (I have done this a few times over the months, however)
3. In Gravity Forms I hard-coded the email address into the sender field rather than using the {admin_email} merge tag

(In hindsight, I should have done these separately – I know 🤦🏻‍♂️)

So the questions are…

1. Does WordPress send WooCommerce Emails out independently of the Easy Wp SMTP plugin?

2. Why would emails sent via Gravity Forms get delivered to my own email but not to the clients (which is also the admin email if this has any bearing)?

3. Why are the emails now working after adding a DMARC and hard-coding the sender’s email

My guess is the answer lies somewhere within hard-coding the email address rather than using the {admin_email} merge tag – but I’d be keen to hear others’ thoughts.

Thanks in advance 👍🏼