how do you access s3 and ssm

[jceaser]

I'm spinning my wheels over here looking for a working example of how to access SSM parameters and also contents of a file hosted on a local s3 bucket from inside a lambda function. Are these uses cases not supported? How best should I handle calls from boto3 which throw UnrecognizedClientException ("The security token included in the request is invalid.")?

I also get "An error occurred (InvalidAccessKeyId) when calling the GetObject operation: The AWS Access Key Id you provided does not exist in our records" when trying to access an S3 bucket.