I ran into a strange problem. We have to poll a mailbox every 10 minutes and check for new mails (POP3, IMAP). We tested our implementation with several mail providers (gmail, 1and1, web.de, gmx, ...) and all worked fine. 

Now we have to use a mailbox from outlook.office365.com with POP3 and SSL. Starting our service everything is working, but after a few hours the mailbox check throws errors while opening the mailbox store.

```
javax.mail.MessagingException: Connect failed;
  nested exception is:
javax.net.ssl.SSLException: java.lang.RuntimeException: Could not generate DH keypair
at com.sun.mail.pop3.POP3Store.protocolConnect(POP3Store.java:210)
at javax.mail.Service.connect(Service.java:295)
at com.heiler.hbc.sil.mail.internal.MailerServiceImpl.createStore(MailerServiceImpl.java:298)
at com.heiler.hbc.sil.mail.internal.MailerServiceImpl.retrieveMails(MailerServiceImpl.java:499)
at com.heiler.hbc.sil.mail.internal.MailerServiceImpl.accessMailbox(MailerServiceImpl.java:180)
at sun.reflect.GeneratedMethodAccessor1272.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
at org.springframework.osgi.service.importer.support.internal.aop.ServiceInvoker.doInvoke(ServiceInvoker.java:58)
at org.springframework.osgi.service.importer.support.internal.aop.ServiceInvoker.invoke(ServiceInvoker.java:62)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.support.DelegatingIntroductionInterceptor.doProceed(DelegatingIntroductionInterceptor.java:132)
at org.springframework.aop.support.DelegatingIntroductionInterceptor.invoke(DelegatingIntroductionInterceptor.java:120)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.osgi.service.util.internal.aop.ServiceTCCLInterceptor.invokeUnprivileged(ServiceTCCLInterceptor.java:56)
at org.springframework.osgi.service.util.internal.aop.ServiceTCCLInterceptor.invoke(ServiceTCCLInterceptor.java:39)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.osgi.service.importer.support.LocalBundleContextAdvice.invoke(LocalBundleContextAdvice.java:59)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.support.DelegatingIntroductionInterceptor.doProceed(DelegatingIntroductionInterceptor.java:132)
at org.springframework.aop.support.DelegatingIntroductionInterceptor.invoke(DelegatingIntroductionInterceptor.java:120)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
at com.sun.proxy.$Proxy323.accessMailbox(Unknown Source)
at com.heiler.hbc.sil.pinquiry.internal.ReceiveResponseService.service(ReceiveResponseService.java:103)
at com.heiler.hbc.sil.pinquiry.internal.ReceiveResponseService.service(ReceiveResponseService.java:34)
at com.heiler.hbc.service.executor.internal.PInquiryCheckMailboxService.execute(PInquiryCheckMailboxService.java:110)
at com.heiler.hbc.service.executor.internal.AbstractSchedulerService.run(AbstractSchedulerService.java:61)
at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:53)
at org.springframework.scheduling.concurrent.ReschedulingRunnable.run(ReschedulingRunnable.java:81)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:178)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:292)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
Caused by: javax.net.ssl.SSLException: java.lang.RuntimeException: Could not generate DH keypair
at sun.security.ssl.Alerts.getSSLException(Alerts.java:208)
at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1884)
at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1842)
at sun.security.ssl.SSLSocketImpl.handleException(SSLSocketImpl.java:1825)
at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1346)
at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1323)
at com.sun.mail.util.SocketFetcher.configureSSLSocket(SocketFetcher.java:548)
at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:352)
at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:207)
at com.sun.mail.pop3.Protocol.<init>(Protocol.java:111)
at com.sun.mail.pop3.POP3Store.getPort(POP3Store.java:261)
at com.sun.mail.pop3.POP3Store.protocolConnect(POP3Store.java:206)
... 37 more
Caused by: java.lang.RuntimeException: Could not generate DH keypair
at sun.security.ssl.ECDHCrypt.<init>(ECDHCrypt.java:80)
at sun.security.ssl.ClientHandshaker.serverKeyExchange(ClientHandshaker.java:632)
at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:218)
at sun.security.ssl.Handshaker.processLoop(Handshaker.java:868)
at sun.security.ssl.Handshaker.process_record(Handshaker.java:804)
at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1016)
at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1312)
at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1339)
... 44 more
Caused by: java.security.InvalidAlgorithmParameterException: parameter object not a ECParameterSpec
at org.bouncycastle.jce.provider.JDKKeyPairGenerator$EC.initialize(Unknown Source)
at sun.security.ssl.ECDHCrypt.<init>(ECDHCrypt.java:75)
... 51 more

```

This is my createStore method:

```
private void createStore() throws MessagingException
  {
if ( store == null )
{
  store = session.getStore( authType.getType() );
}
if ( store != null && !store.isConnected() )
{
  try
  {
    store.connect( popHost, popPort, user, password );
  }
  catch ( MessagingException e )
  {
    store = null;
    logger.error( "Cannot connect to configured mailbox: [Host: " + popHost + ", Port: " + popPort + ", User: " //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
                  + user + "]" ); //$NON-NLS-1$
    logger.debug( "", e );
  }
}
}

```

On store.connect(..) the error occurs.

Anyone out there with an idea what can couse this error?

Thanks
Stephan