Activiti Admin 1.11 stopped working

[nenadteo]

Hello,

we have installed Activiti Admin using manual installation on Tomcat v8.5.57 (we are using PostgreSQL):

https://docs.alfresco.com/process-services1.10/topics/installing_administrator_application.html

We also configured Tomcat process to start automatically on the RHEL VM restart. 

Tomcat process configuration in /etc/systemd/system/alfrescoaps.service:

# Systemd unit file for tomcat
[Unit]
Description=Alfresco Process Services v1.11.0 Application - Activiti Admin (Apache Tomcat Web Application Container)
After=syslog.target network.target

[Service]
Type=forking

Environment=JAVA_HOME=/usr/lib/jvm/jre
Environment=CATALINA_PID=/opt/alfresco/aps/tomcat/temp/tomcat.pid
Environment=CATALINA_HOME=/opt/alfresco/aps/tomcat/
Environment=CATALINA_BASE=/opt/alfresco/aps/tomcat/
Environment='CATALINA_OPTS=-Xms4G -Xmx8G -server -XX:+UseParallelGC'
Environment='JAVA_OPTS=-Djava.awt.headless=true -Djava.security.egd=file:/dev/./urandom'

ExecStart=/opt/alfresco/aps/tomcat/bin/startup.sh
ExecStop=/bin/kill -15 $MAINPID

User=alfresco
Group=alfresco

[Install]
WantedBy=multi-user.target

Activiti Admin monitors 2 Activiti Apps on separate RHEL Servers (also installed manually on the same tomcat version).

We have problem that Tomcat with Activiti Admin for now visible reason stopps working sometimes. Tomcats with Activiti Apps working normally without problems. We see only following infor in Activiti Admin catalina.out file:

22-Jul-2020 18:45:56.505 INFO [main] org.apache.coyote.AbstractProtocol.start Starting ProtocolHandler ["http-nio-8080"]
22-Jul-2020 18:45:56.514 INFO [main] org.apache.coyote.AbstractProtocol.start Starting ProtocolHandler ["https-jsse-nio-8446"]
22-Jul-2020 18:45:56.540 INFO [main] org.apache.coyote.AbstractProtocol.start Starting ProtocolHandler ["ajp-nio-0.0.0.0-8009"]
22-Jul-2020 18:45:56.543 INFO [main] org.apache.catalina.startup.Catalina.start Server startup in 16163 ms
05:03:07 [https-jsse-nio-8446-exec-9] WARN  com.activiti.service.ActivitiEndpointLicenseService  - Error while calling Activiti endpoint: Activiti app - assuming valid license: Read timed out
05:03:13 [https-jsse-nio-8446-exec-7] WARN  com.activiti.service.ActivitiEndpointLicenseService  - Error while calling Activiti endpoint: Activiti app - assuming valid license: Read timed out
05:15:00 [activiti-admin-Executor-2] INFO  com.activiti.service.activiti.cluster.ActivitiClusterService  - Node 36489eb8-c82a-445d-9c16-69b2a1ac5d30 was not active for at least 600000 ms. Removing it from the list
05:15:00 [activiti-admin-Executor-2] INFO  com.activiti.service.activiti.cluster.ActivitiClusterService  - Node b62a70c2-4388-4fe1-9c16-1dc7fda38cb8 was not active for at least 600000 ms. Removing it from the list
22-Jul-2020 19:56:45.448 INFO [Thread-12] org.apache.coyote.AbstractProtocol.pause Pausing ProtocolHandler ["http-nio-8080"]
22-Jul-2020 19:56:45.457 INFO [Thread-12] org.apache.coyote.AbstractProtocol.pause Pausing ProtocolHandler ["https-jsse-nio-8446"]
22-Jul-2020 19:56:45.463 INFO [Thread-12] org.apache.coyote.AbstractProtocol.pause Pausing ProtocolHandler ["ajp-nio-0.0.0.0-8009"]
22-Jul-2020 19:56:45.473 INFO [Thread-12] org.apache.catalina.core.StandardService.stopInternal Stopping service [Catalina]
22-Jul-2020 19:56:45.545 WARNING [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [activiti-admin] appears to have started a thread named [activiti-admin-Executor-1] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 java.base@11.0.1/jdk.internal.misc.Unsafe.park(Native Method)
 java.base@11.0.1/java.util.concurrent.locks.LockSupport.park(LockSupport.java:194)
 java.base@11.0.1/java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2081)
 java.base@11.0.1/java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:433)
 java.base@11.0.1/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1054)
 java.base@11.0.1/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1114)
 java.base@11.0.1/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
 java.base@11.0.1/java.lang.Thread.run(Thread.java:834)
22-Jul-2020 19:56:45.545 WARNING [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [activiti-admin] appears to have started a thread named [activiti-admin-Executor-2] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
 java.base@11.0.1/jdk.internal.misc.Unsafe.park(Native Method)
 java.base@11.0.1/java.util.concurrent.locks.LockSupport.park(LockSupport.java:194)
 java.base@11.0.1/java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2081)
 java.base@11.0.1/java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:433)
 java.base@11.0.1/java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1054)
 java.base@11.0.1/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1114)
 java.base@11.0.1/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
 java.base@11.0.1/java.lang.Thread.run(Thread.java:834)
22-Jul-2020 19:56:45.575 INFO [Thread-12] org.apache.coyote.AbstractProtocol.stop Stopping ProtocolHandler ["http-nio-8080"]
22-Jul-2020 19:56:45.583 INFO [Thread-12] org.apache.coyote.AbstractProtocol.stop Stopping ProtocolHandler ["https-jsse-nio-8446"]
22-Jul-2020 19:56:45.585 INFO [Thread-12] org.apache.coyote.AbstractProtocol.stop Stopping ProtocolHandler ["ajp-nio-0.0.0.0-8009"]
22-Jul-2020 19:56:45.590 INFO [Thread-12] org.apache.coyote.AbstractProtocol.destroy Destroying ProtocolHandler ["http-nio-8080"]
22-Jul-2020 19:56:45.591 INFO [Thread-12] org.apache.coyote.AbstractProtocol.destroy Destroying ProtocolHandler ["https-jsse-nio-8446"]
22-Jul-2020 19:56:45.592 INFO [Thread-12] org.apache.coyote.AbstractProtocol.destroy Destroying ProtocolHandler ["ajp-nio-0.0.0.0-8009"]

Do you know maybe what could be the reason?

Thank you in advance.