Pushnotifications module, scheduled event hanging

We are on Mx 7.23.7 and using pushnotifications connector version 3.0.1 Several times per week we send about 7000 pushnotifications to Android and iOS devices. For Android FCM has been configured, for iOS we configured APNS as messaging service. Until recently we haven’t had issues for a long time. We didn’t make changes to the pushnotification module or the way it has been called by our application for a long time. Only recently did we refresh the Apple pushnotification certificate, although the issue might have occurred before that. The issue is that scheduled event FlushMessageQueue (MF SendMessages) seems to hang at Java action SendAPNSMessage_Impl.  As soon as we notice this we kill the microflow and then the next execution of the scheduled event tries again. Eventually we manage to get all the pushnotifications sent. Anyone an idea what might be the issue ? The log doesn’t give clues.  
1 answers

As multiple triggers of the same function does seem to do the trick, why not create a batch functionality for the schedued event to allow all messages to be send?

Did you also check the monitoring, maybe a memory issue is occurring?