Scheduled Tasks Execution suddenly stops, Railo Access-Logs (and others) are not written

Version Lucee final
Betriebssystem Windows Server 2012 (6.2) 64bit
Servlet Container Apache Tomcat/8.0.24
Java 1.8.0_45 (Oracle Corporation) 64bit

Since 1.9.2016 we have the phenomenon that that the railo-access-logs end
some minutes after midnight. After restarting the service the logs are
written but with the new day they end some minutes after midnight again.
10 days ago we detected that all tasks defined in a lucee web didn´t run.
Restarting the sevice is not really a solution for that.
Has anybody an idea where to look for reason for that? Most logs have a gap
so that we can not track whats happening.

Thanks, Martin