In a video conference, there will be a chance of a black screen

Dear sir:
In a video conference, there will be a chance of a black screen

From JVB and Jicofo log, I found the following error message:

JVB:
JVB 2020-06-29 21:29:23.477 INFO: [2061831] org.ice4j.stack.StunClientTransaction.run() A client tran retransmission failed
java.nio.channels.ClosedByInterruptException
at java.nio.channels.spi.AbstractInterruptibleChannel.end(AbstractInterruptibleChannel.java:202)
at sun.nio.ch.SocketChannelImpl.write(SocketChannelImpl.java:478)
at java.nio.channels.Channels.writeFullyImpl(Channels.java:78)
at java.nio.channels.Channels.writeFully(Channels.java:98)
at java.nio.channels.Channels.access$000(Channels.java:61)
at java.nio.channels.Channels$1.write(Channels.java:174)
at org.ice4j.socket.TCPOutputStream.write(TCPOutputStream.java:95)
at org.ice4j.socket.DelegatingSocket.send(DelegatingSocket.java:740)
at org.ice4j.socket.DelegatingSocket.send(DelegatingSocket.java:732)
at org.ice4j.socket.IceTcpSocketWrapper.send(IceTcpSocketWrapper.java:166)
at org.ice4j.ice.harvest.AbstractTcpListener$PushBackIceSocketWrapper.send(AbstractTcpListener.java:785)
at org.ice4j.stack.Connector.sendMessage(Connector.java:328)
at org.ice4j.stack.NetAccessManager.sendMessage(NetAccessManager.java:654)
at org.ice4j.stack.NetAccessManager.sendMessage(NetAccessManager.java:600)
at org.ice4j.stack.StunClientTransaction.sendRequest0(StunClientTransaction.java:266)
at org.ice4j.stack.StunClientTransaction.access$600(StunClientTransaction.java:50)
at org.ice4j.stack.StunClientTransaction$Retransmitter.run(StunClientTransaction.java:472)
at org.ice4j.util.PeriodicRunnable.executeRun(PeriodicRunnable.java:206)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
JVB 2020-06-29 21:29:23.478 INFO: [2062289] org.ice4j.stack.StunClientTransaction.run() A client tran retransmission failed
java.nio.channels.ClosedChannelException
at sun.nio.ch.SocketChannelImpl.ensureWriteOpen(SocketChannelImpl.java:270)
at sun.nio.ch.SocketChannelImpl.write(SocketChannelImpl.java:461)
at java.nio.channels.Channels.writeFullyImpl(Channels.java:78)
at java.nio.channels.Channels.writeFully(Channels.java:98)
at java.nio.channels.Channels.access$000(Channels.java:61)
at java.nio.channels.Channels$1.write(Channels.java:174)
at org.ice4j.socket.TCPOutputStream.write(TCPOutputStream.java:95)
at org.ice4j.socket.DelegatingSocket.send(DelegatingSocket.java:740)
at org.ice4j.socket.DelegatingSocket.send(DelegatingSocket.java:732)
at org.ice4j.socket.IceTcpSocketWrapper.send(IceTcpSocketWrapper.java:166)
at org.ice4j.ice.harvest.AbstractTcpListener$PushBackIceSocketWrapper.send(AbstractTcpListener.java:785)
at org.ice4j.stack.Connector.sendMessage(Connector.java:328)
at org.ice4j.stack.NetAccessManager.sendMessage(NetAccessManager.java:654)
at org.ice4j.stack.NetAccessManager.sendMessage(NetAccessManager.java:600)
at org.ice4j.stack.StunClientTransaction.sendRequest0(StunClientTransaction.java:266)
at org.ice4j.stack.StunClientTransaction.access$600(StunClientTransaction.java:50)
at org.ice4j.stack.StunClientTransaction$Retransmitter.run(StunClientTransaction.java:472)
at org.ice4j.util.PeriodicRunnable.executeRun(PeriodicRunnable.java:206)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
JVB 2020-06-29 21:29:23.478 SEVERE: [2061857] org.jitsi.impl.neomedia.RTPConnectorOutputStream.log() Failed to send a packet to target /42.236.143.236:57496:java.nio.channels.ClosedChannelException
JVB 2020-06-29 21:29:23.478 SEVERE: [2061857] org.jitsi.impl.neomedia.RTPConnectorOutputStream.log() Failed to send a packet to target /42.236.143.236:57496:java.nio.channels.ClosedChannelException
JVB 2020-06-29 21:29:23.478 SEVERE: [2061838] org.jitsi.impl.neomedia.RTPConnectorOutputStream.log() Failed to send a packet to target /42.236.143.236:57496:java.nio.channels.ClosedChannelException

JICOFO:
Jicofo 2020-06-29 21:31:18.892 INFO: [36] org.jitsi.jicofo.JitsiMeetConferenceImpl.log() Received ICE failed notification from 96855885@conference.172.17.47.228/d3a4171c, session: BridgeSession[id=ff36df_1825fd, bridge=Bridge[jid=jitsi-videobridge.172.17.47.228, relayId=null, region=null]]@482686464

What problem will cause this kind of problem?