eMail Abruf und Versand über Client nicht mehr möglich

Hallo zusammen,

wir haben jLawyer und Debian Linux und 3 Windows Clients am laufen. Die eMail Integration hat bisher soweit funktioniert.
Wenn ich den Posteingang bei einem Anwender aktualisieren möchte, erscheint sofort die Meldung: Keine Verbindung zum Mailserver: Connection failed.
Gehe ich über Einstellungen – Nutzer – eMail und klicke auf „Einstellungen testen“ wird die Konfiguration als Erfolgreich abgeschlossen – die Testmail kommt an.
Vermutlich läuft die Kommunikation bei dem Test über den Server und der Empfang am Client direkt über den Client ?

Das Client-Logfile gibt folgende Meldung aus:
javax.net.ssl.SSLHandshakeException: PKIX path building failed: java.security.cert.CertPathBuilderException: No issuer certificate for certificate in certification path found.

Ich habe jLawyer (Server und Clients) auf die aktuelle Version 1.14.1.0 aktualisiert – der Fehler bleibt. Auch wenn man den Posteingangsserver auf IMAP umstellt.

An dieser Stelle bin ich mir nicht sicher um welches Zertifikat es sich handelt?

Danke für eure Unterstützung.
Gruß
Libor

Nachfolgend noch mehr aus dem Log:

2021-05-16 16:26:46,602 ERROR [com.jdimension.jlawyer.client.mail.EmailInboxPanel] Error connecting to server pop3.strato.de
javax.mail.MessagingException: Connect failed;
nested exception is:
javax.net.ssl.SSLHandshakeException: PKIX path building failed: java.security.cert.CertPathBuilderException: No issuer certificate for certificate in certification path found.
at com.sun.mail.pop3.POP3Store.protocolConnect(POP3Store.java:219)
at javax.mail.Service.connect(Service.java:366)
at javax.mail.Service.connect(Service.java:246)
at com.jdimension.jlawyer.client.mail.EmailInboxPanel.connect(EmailInboxPanel.java:901)
at com.jdimension.jlawyer.client.mail.EmailInboxPanel.refreshFolders(EmailInboxPanel.java:956)
at com.jdimension.jlawyer.client.mail.EmailInboxPanel.cmdRefreshActionPerformed(EmailInboxPanel.java:1499)
at com.jdimension.jlawyer.client.mail.EmailInboxPanel.access$2600(EmailInboxPanel.java:753)
at com.jdimension.jlawyer.client.mail.EmailInboxPanel$21.actionPerformed(EmailInboxPanel.java:1401)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:289)
at java.awt.Component.processMouseEvent(Component.java:6539)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
at java.awt.Component.processEvent(Component.java:6304)
at java.awt.Container.processEvent(Container.java:2239)
at java.awt.Component.dispatchEventImpl(Component.java:4889)
at java.awt.Container.dispatchEventImpl(Container.java:2297)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4904)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4535)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4476)
at java.awt.Container.dispatchEventImpl(Container.java:2283)
at java.awt.Window.dispatchEventImpl(Window.java:2746)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:760)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:84)
at java.awt.EventQueue$4.run(EventQueue.java:733)
at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:730)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:205)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
Caused by: javax.net.ssl.SSLHandshakeException: PKIX path building failed: java.security.cert.CertPathBuilderException: No issuer certificate for certificate in certification path found.
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.HandshakeContext.dispatch(HandshakeContext.java:422)
at sun.security.ssl.TransportContext.dispatch(TransportContext.java:182)
at sun.security.ssl.SSLTransport.decode(SSLTransport.java:149)
at sun.security.ssl.SSLSocketImpl.decode(SSLSocketImpl.java:1143)
at sun.security.ssl.SSLSocketImpl.readHandshakeRecord(SSLSocketImpl.java:1054)
at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:394)
at com.sun.mail.util.SocketFetcher.configureSSLSocket(SocketFetcher.java:626)
at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:400)
at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:238)
at com.sun.mail.pop3.Protocol.<init>(Protocol.java:118)
at com.sun.mail.pop3.POP3Store.getPort(POP3Store.java:271)
at com.sun.mail.pop3.POP3Store.protocolConnect(POP3Store.java:213)
… 44 more
Suppressed: java.lang.NullPointerException
at com.sun.mail.pop3.Protocol.cleanupAndThrow(Protocol.java:148)
at com.sun.mail.pop3.Protocol.<init>(Protocol.java:122)
… 46 more