Application thread remains in WAITING state forever while using logback - multithreading

Question

In my application, I am using logback as a logging framework. The application isn't making progress. To troubleshoot, I took thread dumps (for approx 60 sec), and see the application thread remains in the WAITING stage forever, at the point where the LOG statement happens.
The below is the snippet of the AsynAppender:
"AsyncAppender-Worker-ASYNC-FILE" #209937 daemon prio=5 os_prio=0 tid=0x00007f0150108800 nid=0x799b waiting on condition [0x00007f01a8b13000]
java.lang.Thread.State: WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
- parking to wait for <0x00000006d9216d20> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039)
at java.util.concurrent.ArrayBlockingQueue.take(ArrayBlockingQueue.java:403)
at ch.qos.logback.core.AsyncAppenderBase$Worker.run(AsyncAppenderBase.java:289)
The below is the snippet of the logback thread:
"logback-6" #807 daemon prio=5 os_prio=0 tid=0x00007f018000b800 nid=0x6b7 waiting on condition [0x00007f0141acd000]
java.lang.Thread.State: WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
- parking to wait for <0x0000000640949190> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039)
at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1088)
at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809)
The below is the snippet of the application thread:
"application-thread-005-5def0e44-fff5-4184-96dc-ee77349c31de-StreamThread-13" #66 prio=5 os_prio=0 tid=0x00007f01f5e9c000 nid=0x56 waiting on condition [0x00007f01468ea000]
java.lang.Thread.State: WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
- parking to wait for <0x00000006d9216fa0> (a java.util.concurrent.locks.ReentrantLock$NonfairSync)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:836)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:870)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1199)
The below are snippets of logback.xml
<?xml version="1.0" encoding="UTF-8"?>
<configuration scan="true" scanPeriod="60 seconds">
<appender name="FILE"
class="ch.qos.logback.core.rolling.RollingFileAppender">
<file>logs/coldStorage.log</file>
<append>false</append>
<rollingPolicy
class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
<fileNamePattern>logs/application.log.%d{yyyy-MM-dd_HH}
</fileNamePattern>
<maxHistory>240</maxHistory>
</rollingPolicy>
<encoder>
<pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} %thread %-5level - %msg
%n</pattern>
</encoder>
</appender>
<appender name="ASYNC-FILE"
class="ch.qos.logback.classic.AsyncAppender">
<queueSize>10000</queueSize>
<discardingThreshold>20</discardingThreshold>
<neverBlock>true</neverBlock>
<appender-ref ref="FILE" />
</appender>
<logger name="com.example.appl" level="ERROR" additivity="false">
<appender-ref ref="ASYNC-FILE" />
<appender-ref ref="ASYNC-STDOUT" />
</logger>
<root level="INFO">
<appender-ref ref="ASYNC-FILE" />
</root>
The application isn't making any progress because the thread remains in the WAITING state forever.
Any inputs what's possible is causing this. I tried to disable FILE altogether, still the same issues.