"Error in assuming instance role" when creating AWS App Runner

Terraform Providers AWS
1

I’m getting this error when creating an AWS App Runner service:

InvalidRequestException: Error in assuming instance role arn:aws:iam::000000000000:role/SandboxAppRunnerServiceRole

This is my TF code:

provider "aws" {
  region = "us-east-1"
}

### ECR ###

resource "aws_ecr_repository" "main" {
  name                 = "MyRepository"
  image_tag_mutability = "MUTABLE"

  force_delete = true

  image_scanning_configuration {
    scan_on_push = true
  }

}

### IAM Role ###

resource "aws_iam_role" "app_runner" {
  name = "SandboxAppRunnerServiceRole"

  assume_role_policy = jsonencode({
    Version = "2012-10-17"
    Statement = [
      {
        Action = "sts:AssumeRole"
        Effect = "Allow"
        Sid    = ""
        Principal = {
          Service = "build.apprunner.amazonaws.com"
        }
      },
    ]
  })
}

resource "aws_iam_role_policy_attachment" "app_runner" {
  role       = aws_iam_role.app_runner.name
  policy_arn = "arn:aws:iam::aws:policy/service-role/AWSAppRunnerServicePolicyForECRAccess"
}

### App Runner ###

# Before running this I'm manually uploading the image to the repository

resource "aws_apprunner_service" "main" {
  service_name = "sandbox-service"

  source_configuration {
    image_repository {
      image_configuration {
        port = "5000"
      }
      image_identifier      = "${aws_ecr_repository.main.repository_url}:latest"
      image_repository_type = "ECR"
    }
  }

  instance_configuration {
    instance_role_arn = aws_iam_role.app_runner.arn
  }

}