[Fixed] "Connection : close" when run with stress test

What will be the problem when run the stress test to my API Gateway?

$ bombardier -c 50 -n 2000 https://xxxx.execute-api.ap-southeast-2.amazonaws.com/dev/endpoint 
Bombarding  https://xxxx.execute-api.ap-southeast-2.amazonaws.com/dev/endpoint with 2000 requests using 50 connections
[==============================================================================================================================================================================] 100.00% 3m0s

Statistics        Avg      Stdev        Max
  Reqs/sec        10.00      33.82        310
  Latency      294.08ms   381.62ms      2.00s
  HTTP codes:
    1xx - 0, 2xx - 1310, 3xx - 0, 4xx - 0, 5xx - 0
    others - 690
    the server closed connection before returning the first response byte. Make sure the server returns 'Connection: close' response header before closing the connection - 690
  Throughput:     3.71KB/s

Check Amazon API Gateway Limits, not sure which one I hit the limits.

I got better performances after adjusted DynamoDB’s ProvisionedThroughput read and write capacity units