rasterio opens file from AWS S3 bucket on local machine, but can't find file when deployed to Google App Engine




I'm trying to run a python flask app, that opens a file hosted on an S3 bucket and analyzes the data. When I deploy the flask app on my local host, it runs like expected. Once I deploy the app to the cloud, it suddenly cannot find the file. I feel like this might be a bug, but i'm too afraid to post in the github. I'll attach the relevant snippet of code, and the error I'm receiving in the GCP Logs. I apologize for terrible formatting as I'm unaware of how to do it properly in this forum.
Here's the code: 

session = boto3.Session(aws_access_key_id=access_key, aws_secret_access_key=secret_access_key)    

def start_process(map, lon, lat):    
    with rasterio.Env(AWSSession(session)):        
        return getCoordinatePixel(map,lon,lat)  url = 's3://metcon-test-bucket/high_plus.tif'  

app = Flask(__name__) @app.route('/api')
def api_id():    
    lat = int(request.args['lat'])    
    lon = int(request.args['lon'])          
    return jsonify(start_process(url, lon, lat))  

if __name__ == '__main__':    

 and here's the error:

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