This one took me ages to figure out why it wasn't working. Basically I had set up SES in us-west-2, but Phabricator always uses us-east-1 (because that is the default set in phabricator/externals/amazon-ses/ses.php). When it fails in this scenario, you get the useless message "Sender is not verified" (when running bin/mail send-test), instead of an error indicating that you might have the wrong region configured.

Since you have to explicitly request production access for SES, I don't want to have to send through another request for us-east-1 (since I already have production access in us-west-2). Instead, Phabricator should have an option under the Amazon configuration to specify the region for SES.