Google Cloud Message Push, Error: No such generator...

[darndt]

I get the following error by enabling Push-Notifications:

2019-04-01T22:23:57,952+0200 ERROR [PushNotificationServiceImpl-0000001] com.openexchange.pns.impl.PushNotificationServiceI mpl$NotificationsHandler.run(PushNotificationServi ceImpl$NotificationsHandler.java:588)
Failed to handle notification(s) with topic ox:mail:new in context 1
com.openexchange.exception.OXException: PNS-0008 Categories=ERROR Message='No such generator for client: open-xchange-mobile-api-facade' exceptionID=-587989707-4
at com.openexchange.exception.OXExceptionFactory.crea te(OXExceptionFactory.java:175)
at com.openexchange.exception.OXExceptionFactory.crea te(OXExceptionFactory.java:165)
at com.openexchange.exception.OXExceptionFactory.crea te(OXExceptionFactory.java:138)
at com.openexchange.pns.PushExceptionCodes.create(Pus hExceptionCodes.java:174)
at com.openexchange.pns.transport.gcm.internal.GcmPus hNotificationTransport.categorize(GcmPushNotificat ionTransport.java:330)
at com.openexchange.pns.transport.gcm.internal.GcmPus hNotificationTransport.transport(GcmPushNotificati onTransport.java:254)
at com.openexchange.pns.transport.gcm.internal.GcmPus hNotificationTransport.transport(GcmPushNotificati onTransport.java:246)
at com.openexchange.pns.impl.PushNotificationServiceI mpl.doHandle(PushNotificationServiceImpl.java:518)
at com.openexchange.pns.impl.PushNotificationServiceI mpl$NotificationsHandler.run(PushNotificationServi ceImpl.java:586)
at com.openexchange.processing.internal.RoundRobinPro cessor$Selector.run(RoundRobinProcessor.java:375)
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:748)


The Dovecot Server send push-notification to OX-App-Suite but then I get this Error. Can anyone help me with this error?