AWS ECS/EC2 task fails to deploy - amazon-web-services

Question

I'm trying to deploy a small React app to an EC2 instance using ECS but I'm constantly getting the error message Resource handler returned message: "Error occurred during operation 'ECS Deployment Circuit Breaker was triggered'." (RequestToken: xxx-xxx-xxx-xxx, HandlerErrorCode: GeneralServiceException)
I have tried deploying the app to an EC2 instance manually (with docker run -p 80:3000 my-app) and this worked fine so I'm pretty sure the app and Dockerfile are ok. The Docker image is hosted in ECR.
I'm thinking that most likely this is an issue with my task definition. It looks like this:
{
"taskDefinitionArn": "arn:aws:ecs:eu-north-1:xxx:task-definition/my-task-definition:4",
"containerDefinitions": [
{
"name": "my-app",
"image": "xxx.dkr.ecr.eu-north-1.amazonaws.com/my-app:latest",
"cpu": 1024,
"memory": 1024,
"portMappings": [
{
"name": "my-app-3000-tcp",
"containerPort": 3000,
"hostPort": 80,
"protocol": "tcp"
}
],
"essential": true,
"environment": [],
"mountPoints": [],
"volumesFrom": [],
"disableNetworking": false,
"privileged": false,
"readonlyRootFilesystem": false,
"pseudoTerminal": false
}
],
"family": "my-app",
"taskRoleArn": "arn:aws:iam::xxx:role/EcsToEcrAccess",
"executionRoleArn": "arn:aws:iam::xxx:role/ecsTaskExecutionRole",
"networkMode": "bridge",
"revision": 4,
"volumes": [],
"status": "ACTIVE",
"requiresAttributes": [
{
"name": "com.amazonaws.ecs.capability.ecr-auth"
},
{
"name": "com.amazonaws.ecs.capability.task-iam-role"
},
{
"name": "ecs.capability.execution-role-ecr-pull"
}
],
"placementConstraints": [],
"compatibilities": [
"EC2"
],
"requiresCompatibilities": [
"EC2"
],
"registeredAt": "2023-01-31T15:30:16.919Z",
"registeredBy": "arn:aws:iam::xxx:user/me",
"tags": [
{
"key": "ecs:taskDefinition:createdFrom",
"value": "ecs-console-v2"
}
]
}