Container instances not being registered from capacity provider

I created an ECS cluster with an Auto Scaling Group capacity provider. The capacity provider shows that there are 2 instances (t2.micro) launched (but they are not listed in the container instances).

I created one (and only) service in the ECS cluster.Task definition:

{"taskDefinitionArn": "arn:aws:ecs:ap-south-1:<acc_id>:task-definition/basic-iris-app-td:3","containerDefinitions": [        {"name": "basic-iris-app","image": "<acc_id>.dkr.ecr.ap-south-1.amazonaws.com/basic-iris-app:latest","cpu": 0,"portMappings": [                {"name": "8080","containerPort": 8080,"hostPort": 8080,"protocol": "tcp","appProtocol": "http"                }            ],"essential": true,"environment": [],"environmentFiles": [],"mountPoints": [],"volumesFrom": [],"ulimits": [],"logConfiguration": {"logDriver": "awslogs","options": {"awslogs-create-group": "true","awslogs-group": "/ecs/basic-iris-app-td","awslogs-region": "ap-south-1","awslogs-stream-prefix": "ecs"                },"secretOptions": []            }        }    ],"family": "basic-iris-app-td","executionRoleArn": "arn:aws:iam::<acc_id>:role/ecsTaskExecutionRole","networkMode": "awsvpc","revision": 3,"volumes": [],"status": "ACTIVE","requiresAttributes": [        {"name": "com.amazonaws.ecs.capability.logging-driver.awslogs"        },        {"name": "ecs.capability.execution-role-awslogs"        },        {"name": "com.amazonaws.ecs.capability.ecr-auth"        },        {"name": "com.amazonaws.ecs.capability.docker-remote-api.1.19"        },        {"name": "ecs.capability.execution-role-ecr-pull"        },        {"name": "com.amazonaws.ecs.capability.docker-remote-api.1.18"        },        {"name": "ecs.capability.task-eni"        },        {"name": "com.amazonaws.ecs.capability.docker-remote-api.1.29"        }    ],"placementConstraints": [],"compatibilities": ["EC2"    ],"requiresCompatibilities": ["EC2"    ],"cpu": "205","memory": "205","runtimePlatform": {"cpuArchitecture": "X86_64","operatingSystemFamily": "LINUX"    },"registeredAt": "2024-01-17T10:20:50.700Z","registeredBy": "arn:aws:iam::<acc_id>:root","tags": []}

The service does not start and fails with an error saying Capacity provider is empty.

I am not able to understand why this is happening and how to fix this.

If required, this is the application I am trying to deploy.

Please let me know if I need to add more info.

I have tried this by adding it to the user data in the ASG's launch template and it did not work.