Quartz scheduled jobs can stop running until restart

org.quartz.SchedulerException: JobListener 'ScheduledJobListener' threw exception: Could not open Hibernate Session for transaction; nested exception is net.sf.hibernate.exception.GenericJDBCException: Cannot open connection [See nested exception: org.springframework.transaction.CannotCreateTransactionException: Could not open Hibernate Session for transaction; nested exception is net.sf.hibernate.exception.GenericJDBCException: Cannot open connection]
	at org.quartz.core.QuartzScheduler.notifyJobListenersToBeExecuted(QuartzScheduler.java:1951)
	at org.quartz.core.JobRunShell.notifyListenersBeginning(JobRunShell.java:364)
	at org.quartz.core.JobRunShell.run(JobRunShell.java:190)
	at com.atlassian.confluence.schedule.quartz.ConfluenceQuartzThreadPool.lambda$runInThread$187(ConfluenceQuartzThreadPool.java:19)
	at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:549)
Caused by: org.springframework.transaction.CannotCreateTransactionException: Could not open Hibernate Session for transaction; nested exception is net.sf.hibernate.exception.GenericJDBCException: Cannot open connection
	at org.springframework.orm.hibernate.HibernateTransactionManager.doBegin(HibernateTransactionManager.java:473)
	at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:374)
	at sun.reflect.GeneratedMethodAccessor49.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:497)
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:198)
	at com.sun.proxy.$Proxy33.getTransaction(Unknown Source)
	at org.springframework.transaction.interceptor.TransactionAspectSupport.createTransactionIfNecessary(TransactionAspectSupport.java:263)
	at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:101)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
	at com.sun.proxy.$Proxy142.jobToBeExecuted(Unknown Source)
	at org.quartz.core.QuartzScheduler.notifyJobListenersToBeExecuted(QuartzScheduler.java:1949)
	... 4 more
Caused by: net.sf.hibernate.exception.GenericJDBCException: Cannot open connection
	at net.sf.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:80)
	at net.sf.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:69)
	at net.sf.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:29)
	at net.sf.hibernate.impl.BatcherImpl.convert(BatcherImpl.java:328)
	at net.sf.hibernate.impl.BatcherImpl.openConnection(BatcherImpl.java:295)
	at net.sf.hibernate.impl.SessionImpl.connection(SessionImpl.java:3367)
	at org.springframework.orm.hibernate.HibernateTransactionManager.doBegin(HibernateTransactionManager.java:422)
	... 17 more
Caused by: java.sql.SQLException: Cannot get a connection, pool error Timeout waiting for idle object
	at org.apache.tomcat.dbcp.dbcp2.PoolingDataSource.getConnection(PoolingDataSource.java:126)
	at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.getConnection(BasicDataSource.java:1412)
	at net.sf.hibernate.connection.DatasourceConnectionProvider.getConnection(DatasourceConnectionProvider.java:59)
	at net.sf.hibernate.impl.BatcherImpl.openConnection(BatcherImpl.java:292)
	... 20 more
	at org.apache.tomcat.dbcp.pool2.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:446)
	at org.apache.tomcat.dbcp.pool2.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:360)
	at org.apache.tomcat.dbcp.dbcp2.PoolingDataSource.getConnection(PoolingDataSource.java:118)
	... 23 more