I am working with a customer to evaluate the "Send through External Email Services" with a Gmail connection.
We have enabled the feature and connected their users' accounts to Gmail.
If they send a 1 off email directly to a Lead/Contact, we get the DKIM, SPF, DMARC results we are expecting. DKIM and SPF both validate with their domain and DMARC alignment succeeds.
If we do a List Send, DKIM and SPF technically pass, but DMARC fail because of alignment. The From address for the SPF record is a salesforce.com one, and not the user's Domain. So while it validates successfully, we miss on alignment.
Is there a configuration I missed or an option we can use to get the List Sends to use the Send through Gmail too? Or is this just not supported yet?