How to solve “I/O error on POST request” from restTemplate

Hi Julia This quite feels like the protocol issue. The AWS is fully TLS 1.2 or higher supporting, but the client is not. The Rest Template if not configured otherwise, will start negotiation with TLS 1.0. You have to forcefully make the client to connect only with 1.2 or 1.3 protocol stacks.

 SSLContext context = SSLContext.getInstance("TLSv1.2");
context.init(null, null, null);

CloseableHttpClient httpClient = HttpClientBuilder.create().setSSLContext(context)
    .build();
HttpComponentsClientHttpRequestFactory factory = new HttpComponentsClientHttpRequestFactory(httpClient);
RestTemplate restTemplate = new RestTemplate(factory);

I/O error on POST request for "http://{ip}:{port}/face/emp"

It seems you do not set a valid host:port

Check your host and reqUri

UriComponents uri = UriComponentsBuilder.fromHttpUrl(host+reqUri).build();