SpringBoot Connection prematurely closed BEFORE response

When the volume of requests is large, such a problem occurs in production, and this problem cannot be reproduced locally. How can I solve this problem?

org.springframework.web.reactive.function.client.WebClientRequestException: Connection prematurely closed BEFORE response; nested exception is reactor.netty.http.client.PrematureCloseException: Connection prematurely closed BEFORE response
    at org.springframework.web.reactive.function.client.ExchangeFunctions$DefaultExchangeFunction.lambda$wrapException$9(ExchangeFunctions.java:141) ~[spring-webflux-5.3.5.jar!/:5.3.5]
    Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException: 
Error has been observed at the following site(s):
    |_ checkpoint ⇢ Request to POST https://www.lh.com/openapi/auth/v1/token/check [DefaultWebClient]
Stack trace:
        at org.springframework.web.reactive.function.client.ExchangeFunctions$DefaultExchangeFunction.lambda$wrapException$9(ExchangeFunctions.java:141) ~[spring-webflux-5.3.5.jar!/:5.3.5]
        at reactor.core.publisher.MonoErrorSupplied.subscribe(MonoErrorSupplied.java:70) ~[reactor-core-3.4.4.jar!/:3.4.4]
        at reactor.core.publisher.Mono.subscribe(Mono.java:4099) ~[reactor-core-3.4.4.jar!/:3.4.4]
        at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onError(FluxOnErrorResume.java:103) ~[reactor-core-3.4.4.jar!/:3.4.4]
        at reactor.core.publisher.FluxPeek$PeekSubscriber.onError(FluxPeek.java:221) ~[reactor-core-3.4.4.jar!/:3.4.4]
        at reactor.core.publisher.FluxPeek$PeekSubscriber.onError(FluxPeek.java:221) ~[reactor-core-3.4.4.jar!/:3.4.4]
        at reactor.core.publisher.FluxPeek$PeekSubscriber.onError(FluxPeek.java:221) ~[reactor-core-3.4.4.jar!/:3.4.4]
        at reactor.core.publisher.MonoNext$NextSubscriber.onError(MonoNext.java:93) ~[reactor-core-3.4.4.jar!/:3.4.4]
        at reactor.core.publisher.MonoFlatMapMany$FlatMapManyMain.onError(MonoFlatMapMany.java:204) ~[reactor-core-3.4.4.jar!/:3.4.4]
        at reactor.core.publisher.SerializedSubscriber.onError(SerializedSubscriber.java:124) ~[reactor-core-3.4.4.jar!/:3.4.4]
        at reactor.core.publisher.FluxRetryWhen$RetryWhenMainSubscriber.whenError(FluxRetryWhen.java:224) ~[reactor-core-3.4.4.jar!/:3.4.4]
        at reactor.core.publisher.FluxRetryWhen$RetryWhenOtherSubscriber.onError(FluxRetryWhen.java:273) ~[reactor-core-3.4.4.jar!/:3.4.4]
        at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.drain(FluxConcatMap.java:413) ~[reactor-core-3.4.4.jar!/:3.4.4]
        at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.onNext(FluxConcatMap.java:250) ~[reactor-core-3.4.4.jar!/:3.4.4]
        at reactor.core.publisher.EmitterProcessor.drain(EmitterProcessor.java:491) ~[reactor-core-3.4.4.jar!/:3.4.4]
        at reactor.core.publisher.EmitterProcessor.tryEmitNext(EmitterProcessor.java:299) ~[reactor-core-3.4.4.jar!/:3.4.4]
        at reactor.core.publisher.SinkManySerialized.tryEmitNext(SinkManySerialized.java:97) ~[reactor-core-3.4.4.jar!/:3.4.4]
        at reactor.core.publisher.InternalManySink.emitNext(InternalManySink.java:27) ~[reactor-core-3.4.4.jar!/:3.4.4]
        at reactor.core.publisher.FluxRetryWhen$RetryWhenMainSubscriber.onError(FluxRetryWhen.java:189) ~[reactor-core-3.4.4.jar!/:3.4.4]
        at reactor.core.publisher.MonoCreate$DefaultMonoSink.error(MonoCreate.java:189) ~[reactor-core-3.4.4.jar!/:3.4.4]
        at reactor.netty.http.client.HttpClientConnect$HttpObserver.onUncaughtException(HttpClientConnect.java:357) ~[reactor-netty-http-1.0.5.jar!/:1.0.5]
        at reactor.netty.ReactorNetty$CompositeConnectionObserver.onUncaughtException(ReactorNetty.java:647) ~[reactor-netty-core-1.0.5.jar!/:1.0.5]
        at reactor.netty.resources.DefaultPooledConnectionProvider$DisposableAcquire.onUncaughtException(DefaultPooledConnectionProvider.java:228) ~[reactor-netty-core-1.0.5.jar!/:1.0.5]
        at reactor.netty.resources.DefaultPooledConnectionProvider$PooledConnection.onUncaughtException(DefaultPooledConnectionProvider.java:476) ~[reactor-netty-core-1.0.5.jar!/:1.0.5]
        at reactor.netty.http.client.HttpClientOperations.onInboundClose(HttpClientOperations.java:290) ~[reactor-netty-http-1.0.5.jar!/:1.0.5]
        at reactor.netty.channel.ChannelOperationsHandler.channelInactive(ChannelOperationsHandler.java:74) ~[reactor-netty-core-1.0.5.jar!/:1.0.5]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:262) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:248) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelInactive(AbstractChannelHandlerContext.java:241) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.channel.ChannelInboundHandlerAdapter.channelInactive(ChannelInboundHandlerAdapter.java:81) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.handler.codec.http.HttpContentDecoder.channelInactive(HttpContentDecoder.java:235) ~[netty-codec-http-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:262) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:248) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelInactive(AbstractChannelHandlerContext.java:241) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.channel.CombinedChannelDuplexHandler$DelegatingChannelHandlerContext.fireChannelInactive(CombinedChannelDuplexHandler.java:418) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.channelInputClosed(ByteToMessageDecoder.java:389) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.channelInactive(ByteToMessageDecoder.java:354) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.handler.codec.http.HttpClientCodec$Decoder.channelInactive(HttpClientCodec.java:311) ~[netty-codec-http-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.channel.CombinedChannelDuplexHandler.channelInactive(CombinedChannelDuplexHandler.java:221) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:262) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:248) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelInactive(AbstractChannelHandlerContext.java:241) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.channelInputClosed(ByteToMessageDecoder.java:389) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.channelInactive(ByteToMessageDecoder.java:354) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.handler.ssl.SslHandler.channelInactive(SslHandler.java:1122) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:262) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:248) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelInactive(AbstractChannelHandlerContext.java:241) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.channel.DefaultChannelPipeline$HeadContext.channelInactive(DefaultChannelPipeline.java:1405) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:262) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:248) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.channel.DefaultChannelPipeline.fireChannelInactive(DefaultChannelPipeline.java:901) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.channel.AbstractChannel$AbstractUnsafe$8.run(AbstractChannel.java:819) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:384) ~[netty-transport-native-epoll-4.1.60.Final-linux-x86_64.jar!/:4.1.60.Final]
        at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) ~[netty-all-4.1.60.Final.jar!/:4.1.60.Final]
        at java.lang.Thread.run(Thread.java:775) ~[na:1.8.0_242]
Caused by: reactor.netty.http.client.PrematureCloseException: Connection prematurely closed BEFORE response

Comment From: wilkinsona

That appears to be a server-side problem. https://www.lh.com has closed the connection before the client has received the response. Unfortunately, there's nothing we can do about that. If you believe that, for some reason, it is a client-side problem, you may want to raise it with the Reactor Netty team.