Fargate task stuck on Pending state

Hello, I've ceated an ECS service with private subnet (no internet access) In the Task Definition, the role for image pull is the default predefined ECS rule. In order to allow communication towards ECR, I've created ecr-api endpoint, ecr-dkr enpoint and an s3 endpoint gateway using the very same subnet used in the service. The problem is that the Fargate service tasks are stuck in pending state. If I create a service with the same Task Definition using a public subnet of the default VPC, everything is working well. If I connect an instance to the private subnet I see that the ecr hostname is translated into local address. What am I missing?