Could you explain meaning of errors log

Shortly, this is small test to check request to one endpoint (function - search)to know does it take 200 request per second during 300 seconds
Tests start normally but very quickly appears errors number 1 from the list below (this is logical error, I get it)
but next goes  
**handshake timed out** - I dunno what it is
next:
**Failed to open a socket. -** the same

--> TimeoutException: Request timeout to not-connected after 60000 ms - when appears this error in out office internet connection temporariry goes off

and then

.UnknownHostException

If someone can explain it to me, it will be very useful, I guess, for many users


al httpsProtocol = http
  .baseURL("https://tv710y0dai.execute-api.us-east-1.amazonaws.com/test/api/v1/")
  
 object Homepage {
  val homepage = exec(http("landing")
    .get("institutions/search?query=abacu&stateId=9&sortBy=ranking")
   .check(status.is(200)))
 }

 val users = scenario("Users").exec(Homepage.homepage);

 setUp(
  users.inject(constantUsersPerSec(200) during (300 seconds))
 ).protocols(httpsProtocol)
}

1) 15:00:49.838 [WARN ] i.g.h.a.ResponseProcessor - Request ‘landing’ failed: status.find.is(200), but actually found 502

2) 15:02:39.470 [WARN ] i.g.h.a.ResponseProcessor - Request ‘landing’ failed: j.n.ConnectException: handshake timed out

3) 15:02:43.126 [WARN ] i.g.h.a.ResponseProcessor - Request ‘landing’ failed: j.n.ConnectException: Failed to open a socket.

4) 15:02:50.821 [WARN ] i.g.h.a.ResponseProcessor - Request ‘landing’ failed: j.u.c.TimeoutException: Request timeout to not-connected after 60000 ms

5) j.n**.UnknownHostException**: blablabla.blablabla.amazonaws.com 16008 (41.93%)

1) 15:00:49.838 [WARN ] i.g.h.a.ResponseProcessor - Request ‘landing’ failed: status.find.is(200), but actually found 502

Server side error when processing this request.

4) 15:02:50.821 [WARN ] i.g.h.a.ResponseProcessor - Request ‘landing’ failed: j.u.c.TimeoutException: Request timeout to not-connected after 60000 ms

f
– by default Gatling scripts request timeouts after 60 seconds.you can change that in “gatling.conf”

yet, can’t get the nature of this error:

j.n.UnknownHostException: test-10-----2.us-east-1.elb.amazon 1 (25.00%)

aws.com: nodename nor servname provided, or not known