# High level REST client returns error 503 randomly

**URL:** <https://discuss.elastic.co/t/high-level-rest-client-returns-error-503-randomly/127356>\
**Category:** Elasticsearch\
**Created:** [April 9, 2018, 4:41pm UTC](https://discuss.elastic.co/t/high-level-rest-client-returns-error-503-randomly/127356 "2018-04-09T16:41:06Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![hanyi8000](https://avatars.discourse-cdn.com/v4/letter/h/ecccb3/32.png) [@hanyi8000](https://discuss.elastic.co/u/hanyi8000)\
**Post date:** [April 9, 2018, 4:41pm UTC](https://discuss.elastic.co/t/high-level-rest-client-returns-error-503-randomly/127356/1 "2018-04-09T16:41:06Z")

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Hi all,

We use High level REST client to communicate to Elastichsearch 6.0, however it randomly returns 503 error, I'm guessing it's due to some timeout issue but we can not be sure the root cause. Below is our exception stack:

javax.net.ssl.SSLKeyException: RSA premaster secret error  
at sun.security.ssl.Handshaker.checkThrown(Handshaker.java:1532)  
at sun.security.ssl.SSLEngineImpl.checkTaskThrown(SSLEngineImpl.java:535)  
at sun.security.ssl.SSLEngineImpl.readNetRecord(SSLEngineImpl.java:813)  
at sun.security.ssl.SSLEngineImpl.unwrap(SSLEngineImpl.java:781)  
at javax.net.ssl.SSLEngine.unwrap(SSLEngine.java:624)  
at org.apache.http.nio.reactor.ssl.SSLIOSession.doUnwrap(SSLIOSession.java:273)  
at org.apache.http.nio.reactor.ssl.SSLIOSession.doHandshake(SSLIOSession.java:328)  
at org.apache.http.nio.reactor.ssl.SSLIOSession.isAppInputReady(SSLIOSession.java:509)  
at org.apache.http.impl.nio.reactor.AbstractIODispatch.inputReady(AbstractIODispatch.java:120)  
at org.apache.http.impl.nio.reactor.BaseIOReactor.readable(BaseIOReactor.java:162)  
at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvent(AbstractIOReactor.java:337)  
at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvents(AbstractIOReactor.java:315)  
at org.apache.http.impl.nio.reactor.AbstractIOReactor.execute(AbstractIOReactor.java:276)  
at org.apache.http.impl.nio.reactor.BaseIOReactor.execute(BaseIOReactor.java:104)  
at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor$Worker.run(AbstractMultiworkerIOReactor.java:588)  
at java.lang.Thread.run(Thread.java:748)  
Caused by: javax.net.ssl.SSLKeyException: RSA premaster secret error  
at sun.security.ssl.RSAClientKeyExchange.(RSAClientKeyExchange.java:87)  
at sun.security.ssl.ClientHandshaker.serverHelloDone(ClientHandshaker.java:962)  
at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:348)  
at sun.security.ssl.Handshaker.processLoop(Handshaker.java:1052)  
at sun.security.ssl.Handshaker$1.run(Handshaker.java:992)  
at sun.security.ssl.Handshaker$1.run(Handshaker.java:989)  
at java.security.AccessController.doPrivileged(Native Method)  
at sun.security.ssl.Handshaker$DelegatedTask.run(Handshaker.java:1467)  
at org.apache.http.nio.reactor.ssl.SSLIOSession.doRunTask(SSLIOSession.java:283)  
at org.apache.http.nio.reactor.ssl.SSLIOSession.doHandshake(SSLIOSession.java:353)  
... 9 more  
Caused by: java.security.NoSuchAlgorithmException: SunTls12RsaPremasterSecret KeyGenerator not available  
at javax.crypto.KeyGenerator.(KeyGenerator.java:169)  
at javax.crypto.KeyGenerator.getInstance(KeyGenerator.java:223)  
at sun.security.ssl.JsseJce.getKeyGenerator(JsseJce.java:251)  
at sun.security.ssl.RSAClientKeyExchange.(RSAClientKeyExchange.java:78)  
... 18 more

And this is our client configuration:

port=443  
scheme=https  
connectNum=50  
connectPerRoute=10

Could anyone give a clue on this?

Thanks.

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [May 7, 2018, 4:41pm UTC](https://discuss.elastic.co/t/high-level-rest-client-returns-error-503-randomly/127356/2 "2018-05-07T16:41:15Z")

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Closed on May 7, 2018, 4:41pm UTC

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