To follow the recently updated email best practices (enforced as of 6/2024) that most marketing platforms and ESPs already have available for their clients.

API calls made to Amazon SES need to include the List-Unsubscribe and the List-Unsubscribe-Post headers in the email payload sent to SES. The header should follow the format specified in RFC 2369 and RFC 8058.

Email deliverability for bulk senders without the list-unsubscribe in the header has tanked since this started getting enforced and smtp through GHL is no longer a viable option for anyone with email lists over 5,000.

Ticket 2669369 has the full response from Amazon SES support.

P.S. My partner says posting this is a waste of time as SES bounce and complaint handling required custom coding on our end (something that GHL could have done long ago). Hoping this can be implemented quickly and we'll be pleasantly surprised!