Unable to create datasource on Hosted grafana

Grafana
2

You cannot use a credentials file on Hosted Grafana as you say. You should be able to do it with an Access and Secret instead. Sounds like you might not have configured it correctly?

Here is our Cloudwatch policy. Are you missing any of these actions (especially the 3 cloudwatch actions)?

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Action": [
                "autoscaling:Describe*",
                "cloudwatch:Describe*",
                "cloudwatch:Get*",
                "cloudwatch:List*",
                "logs:Get*",
                "logs:Describe*",
                "logs:TestMetricFilter",
                "sns:Get*",
                "sns:List*"
            ],
            "Effect": "Allow",
            "Resource": "*"
        }
    ]
}

You might need some extra permissions for EC2 if you are querying that data: