Not accepted Certificate, need help with it please, Thanks.

[Sosook]

Exception in thread "main" java.lang.RuntimeException: javax.net.ssl.SSLHandshakeException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at com.google.common.base.Throwables.propagate(Throwables.java:160)
at com.atlassian.httpclient.apache.httpcomponents.ApacheAsyncHttpClient$6.apply(ApacheAsyncHttpClient.java:402)
at com.atlassian.httpclient.apache.httpcomponents.ApacheAsyncHttpClient$6.apply(ApacheAsyncHttpClient.java:396)
at com.atlassian.util.concurrent.Promises$Of$2.apply(Promises.java:259)
at com.atlassian.util.concurrent.Promises$Of$2.apply(Promises.java:256)
at com.atlassian.util.concurrent.Promises$2.onFailure(Promises.java:162)
at com.google.common.util.concurrent.Futures$4.run(Futures.java:1145)
at com.google.common.util.concurrent.MoreExecutors$SameThreadExecutorService.execute(MoreExecutors.java:293)
at com.google.common.util.concurrent.ExecutionList$RunnableExecutorPair.execute(ExecutionList.java:150)
at com.google.common.util.concurrent.ExecutionList.execute(ExecutionList.java:135)
at com.google.common.util.concurrent.AbstractFuture.setException(AbstractFuture.java:203)
at com.google.common.util.concurrent.SettableFuture.setException(SettableFuture.java:68)
at com.atlassian.httpclient.apache.httpcomponents.SettableFuturePromiseHttpPromiseAsyncClient$1$2.run(SettableFuturePromiseHttpPromiseAsyncClient.java:59)
at com.atlassian.httpclient.apache.httpcomponents.SettableFuturePromiseHttpPromiseAsyncClient$ThreadLocalDelegateRunnable$1.run(SettableFuturePromiseHttpPromiseAsyncClient.java:197)
at com.atlassian.httpclient.apache.httpcomponents.SettableFuturePromiseHttpPromiseAsyncClient.runInContext(SettableFuturePromiseHttpPromiseAsyncClient.java:90)
at com.atlassian.httpclient.apache.httpcomponents.SettableFuturePromiseHttpPromiseAsyncClient$ThreadLocalDelegateRunnable.run(SettableFuturePromiseHttpPromiseAsyncClient.java:192)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:750)
Caused by: javax.net.ssl.SSLHandshakeException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at sun.security.ssl.Alert.createSSLException(Alert.java:131)
at sun.security.ssl.TransportContext.fatal(TransportContext.java:324)
at sun.security.ssl.TransportContext.fatal(TransportContext.java:267)
at sun.security.ssl.TransportContext.fatal(TransportContext.java:262)
at sun.security.ssl.CertificateMessage$T12CertificateConsumer.checkServerCerts(CertificateMessage.java:654)
at sun.security.ssl.CertificateMessage$T12CertificateConsumer.onCertificate(CertificateMessage.java:473)
at sun.security.ssl.CertificateMessage$T12CertificateConsumer.consume(CertificateMessage.java:369)
at sun.security.ssl.SSLHandshake.consume(SSLHandshake.java:377)
at sun.security.ssl.HandshakeContext.dispatch(HandshakeContext.java:444)
at sun.security.ssl.SSLEngineImpl$DelegatedTask$DelegatedAction.run(SSLEngineImpl.java:981)
at sun.security.ssl.SSLEngineImpl$DelegatedTask$DelegatedAction.run(SSLEngineImpl.java:968)
at java.security.AccessController.doPrivileged(Native Method)
at sun.security.ssl.SSLEngineImpl$DelegatedTask.run(SSLEngineImpl.java:915)
at org.apache.http.nio.reactor.ssl.SSLIOSession.doRunTask(SSLIOSession.java:281)
at org.apache.http.nio.reactor.ssl.SSLIOSession.doHandshake(SSLIOSession.java:351)
at org.apache.http.nio.reactor.ssl.SSLIOSession.isAppInputReady(SSLIOSession.java:507)
at org.apache.http.impl.nio.reactor.AbstractIODispatch.inputReady(AbstractIODispatch.java:122)
at org.apache.http.impl.nio.reactor.BaseIOReactor.readable(BaseIOReactor.java:164)
at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvent(AbstractIOReactor.java:339)
at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvents(AbstractIOReactor.java:317)
at org.apache.http.impl.nio.reactor.AbstractIOReactor.execute(AbstractIOReactor.java:278)
at org.apache.http.impl.nio.reactor.BaseIOReactor.execute(BaseIOReactor.java:106)
at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor$Worker.run(AbstractMultiworkerIOReactor.java:590)
... 1 more
Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:456)
at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:323)
at sun.security.validator.Validator.validate(Validator.java:271)
at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:315)
at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:278)
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:141)
at sun.security.ssl.CertificateMessage$T12CertificateConsumer.checkServerCerts(CertificateMessage.java:632)
... 19 more
Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at sun.security.provider.certpath.SunCertPathBuilder.build(SunCertPathBuilder.java:141)
at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:126)
at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:280)
at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:451)
... 25 more