Hi, has anyone encountered where the email campaign only sends to some of the emails in the list?
my AWS SES is still on sandbox, perhaps that's what's causing it?
When your Amazon SES account is still in sandbox mode, you must verify the 'To' email address in addition to the 'From' email address, then your email can be sent through. If you don't verify the 'To' email address, your email will not be sent to that email.
Hence, please move out of sandbox mode as per the instructions in the Get Started Guide by filling up the form → https://aws.amazon.com/ses/extendedaccessrequest.
For more info on filling up the request form, please see → https://sendy.co/troubleshooting#moving-out-of-amazon-ses-sandbox-mode