SES emails send from ECS containers not being delivered

Within our account 183395143814, we are running 1 ECS service in Mumbai and 1 ECS service in Canada, both with the same container image. The service in Mumbai runs uses Fargate as the capacity provider, while the one in Canada uses EC2 as the capacity provider. Emails sent from the service in Mumbai get delivered to recipients correctly. However, emails sent from the service in Canada are not getting delivered. In both regions, the tasks and EC2 instances are configured to use IAM roles that allow sending emails via SES. SNS logging shows that emails get sent from the containers to SES and no error is received. There are no bounces, rejects or complaints.