Blocked Thread Exception While Using BR-POP and Socket - sockets

Question

We have running 1 vert.x Server connected with redis and DB for running Messenger App.
5~7 people(client) connected to redis simultaneously.
when we send a message to others or do some task processing via Web Socket.
WARNING: Thread Thread[vert.x-worker-thread-4,5,main] has been blocked for 74241 ms, time limit is 60000
io.vertx.core.VertxException: Thread blocked
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.socketRead(Unknown Source)
at java.net.SocketInputStream.read(Unknown Source)
at java.net.SocketInputStream.read(Unknown Source)
at java.net.SocketInputStream.read(Unknown Source)
at redis.clients.util.RedisInputStream.ensureFill(RedisInputStream.java:195)
at redis.clients.util.RedisInputStream.readByte(RedisInputStream.java:40)
at redis.clients.jedis.Protocol.process(Protocol.java:141)
at redis.clients.jedis.Protocol.read(Protocol.java:205)
at redis.clients.jedis.Connection.readProtocolWithCheckingBroken(Connection.java:297)
at redis.clients.jedis.Connection.getBinaryMultiBulkReply(Connection.java:233)
at redis.clients.jedis.Connection.getMultiBulkReply(Connection.java:226)
at redis.clients.jedis.Jedis.brpop(Jedis.java:1716)
at redis.clients.jedis.Jedis.brpop(Jedis.java:3400)
at com.ontheit.redis.clients.AbstractRedisClient.BRPOP(AbstractRedisClient.java:59)
at com.ontheit.redis.clients.AbstractRedisClient.BRPOP(AbstractRedisClient.java:50)
at com.ontheit.redis.clients.RedisRequestDaemonClient.getNotify(RedisRequestDaemonClient.java:147)
at com.ontheit.vertx.cache.CacheWorkVerticle.lambda$0(CacheWorkVerticle.java:27)
at com.ontheit.vertx.cache.CacheWorkVerticle$$Lambda$80/1754003563.handle(Unknown Source)
at io.vertx.core.impl.ContextImpl.lambda$executeBlocking$1(ContextImpl.java:273)
at io.vertx.core.impl.ContextImpl$$Lambda$85/1241209246.run(Unknown Source)
at io.vertx.core.impl.TaskQueue.run(TaskQueue.java:76)
at io.vertx.core.impl.TaskQueue$$Lambda$9/1676010932.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
at java.lang.Thread.run(Unknown Source)
we got this warning
we cant understand that warning came out with current circumstance.
we also can't understand why clients number is too high compare to real user who is using redis server.
how can we solved this?