Nignx：Nginx on CentOS7 not properly proxying gRPC requests

Question

Nginx

[root@iZwz95s4gvalnfiqt0jxleZ nginx]# sbin/nginx -V
nginx version: nginx/1.24.0
built by gcc 4.8.5 20150623 (Red Hat 4.8.5-44) (GCC) 
built with OpenSSL 1.0.2k-fips  26 Jan 2017
TLS SNI support enabled
configure arguments: --prefix=/home/nginx --with-http_stub_status_module --with-http_ssl_module --with-http_v2_module

nginx.conf

server {
    listen 9181 ssl http2;
    server_name website;

    ssl_certificate      ../cert/ssl/2023/*.pem;
    ssl_certificate_key  ../cert/ssl/2023/*.key;

    ssl_session_cache    shared:SSL:1m;
    ssl_session_timeout  5m;

    ssl_ciphers  HIGH:!aNULL:!MD5;
    ssl_prefer_server_ciphers  on;

    location / {
        grpc_pass grpc://127.0.0.1:9081;
    }
}

firewall

[root@iZwz95s4gvalnfiqt0jxleZ nginx]# firewall-cmd --list-port
80/tcp 443/tcp 7200/tcp 8200/tcp 8201/tcp 6379/tcp 8000/tcp 9090/tcp 9092/tcp 9094/tcp 8080/tcp 9999/tcp 9876/tcp 9199/tcp 10909/tcp 10911-10912/tcp 9080-9081/tcp 9300/tcp 9181/tcp

server 9081 is running

[root@iZwz95s4gvalnfiqt0jxleZ ~]# lsof -i:9081
COMMAND   PID USER   FD   TYPE    DEVICE SIZE/OFF NODE NAME
java    12641 root  264u  IPv6 481915475      0t0  TCP *:9081 (LISTEN)

All I can say for sure is that the firewall on the cloud server also opens the corresponding ports.At the time, when I tried to do something about the service, it was denied.

java.lang.IllegalStateException: Expected the service ProducerImpl-0 [FAILED] to be RUNNING, but the service has FAILED
    at org.apache.rocketmq.shaded.com.google.common.util.concurrent.AbstractService.checkCurrentState(AbstractService.java:381)
    at org.apache.rocketmq.shaded.com.google.common.util.concurrent.AbstractService.awaitRunning(AbstractService.java:305)
    at org.apache.rocketmq.shaded.com.google.common.util.concurrent.AbstractIdleService.awaitRunning(AbstractIdleService.java:165)
    at org.apache.rocketmq.client.java.impl.producer.ProducerBuilderImpl.build(ProducerBuilderImpl.java:93)
    at com.xmzn.common.mq.producer.SyncProducer.sendMessage(SyncProducer.java:30)
    at com.xmzn.common.mq.producer.SyncProducer.main(SyncProducer.java:47)
Caused by: java.util.concurrent.ExecutionException: org.apache.rocketmq.shaded.io.grpc.StatusRuntimeException: INTERNAL: http2 exception
    at org.apache.rocketmq.shaded.com.google.common.util.concurrent.AbstractFuture.getDoneValue(AbstractFuture.java:588)
    at org.apache.rocketmq.shaded.com.google.common.util.concurrent.AbstractFuture.get(AbstractFuture.java:567)
    at org.apache.rocketmq.shaded.com.google.common.util.concurrent.FluentFuture$TrustedFuture.get(FluentFuture.java:91)
    at org.apache.rocketmq.client.java.impl.ClientImpl.startUp(ClientImpl.java:188)
    at org.apache.rocketmq.client.java.impl.producer.ProducerImpl.startUp(ProducerImpl.java:114)
    at org.apache.rocketmq.shaded.com.google.common.util.concurrent.AbstractIdleService$DelegateService$1.run(AbstractIdleService.java:62)
    at org.apache.rocketmq.shaded.com.google.common.util.concurrent.Callables.lambda$threadRenaming$3(Callables.java:103)
    at java.base/java.lang.Thread.run(Thread.java:1583)
Caused by: org.apache.rocketmq.shaded.io.grpc.StatusRuntimeException: INTERNAL: http2 exception
    at org.apache.rocketmq.shaded.io.grpc.Status.asRuntimeException(Status.java:539)
    at org.apache.rocketmq.shaded.io.grpc.stub.ClientCalls$UnaryStreamToFuture.onClose(ClientCalls.java:544)
    at org.apache.rocketmq.shaded.io.grpc.PartialForwardingClientCallListener.onClose(PartialForwardingClientCallListener.java:39)
    at org.apache.rocketmq.shaded.io.grpc.ForwardingClientCallListener.onClose(ForwardingClientCallListener.java:23)
    at org.apache.rocketmq.shaded.io.grpc.ForwardingClientCallListener$SimpleForwardingClientCallListener.onClose(ForwardingClientCallListener.java:40)
    at org.apache.rocketmq.shaded.io.grpc.internal.DelayedClientCall$DelayedListener$3.run(DelayedClientCall.java:471)
    at org.apache.rocketmq.shaded.io.grpc.internal.DelayedClientCall$DelayedListener.delayOrExecute(DelayedClientCall.java:435)
    at org.apache.rocketmq.shaded.io.grpc.internal.DelayedClientCall$DelayedListener.onClose(DelayedClientCall.java:468)
    at org.apache.rocketmq.shaded.io.grpc.internal.ClientCallImpl.closeObserver(ClientCallImpl.java:563)
    at org.apache.rocketmq.shaded.io.grpc.internal.ClientCallImpl.access$300(ClientCallImpl.java:70)
    at org.apache.rocketmq.shaded.io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$1StreamClosed.runInternal(ClientCallImpl.java:744)
    at org.apache.rocketmq.shaded.io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$1StreamClosed.runInContext(ClientCallImpl.java:723)
    at org.apache.rocketmq.shaded.io.grpc.internal.ContextRunnable.run(ContextRunnable.java:37)
    at org.apache.rocketmq.shaded.io.grpc.internal.SerializingExecutor.run(SerializingExecutor.java:133)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
    ... 1 common frames omitted
Caused by: org.apache.rocketmq.shaded.io.grpc.netty.shaded.io.netty.handler.codec.http2.Http2Exception: First received frame was not SETTINGS. Hex dump for first 5 bytes: 485454502f
    at org.apache.rocketmq.shaded.io.grpc.netty.shaded.io.netty.handler.codec.http2.Http2Exception.connectionError(Http2Exception.java:109)
    at org.apache.rocketmq.shaded.io.grpc.netty.shaded.io.netty.handler.codec.http2.Http2ConnectionHandler$PrefaceDecoder.verifyFirstFrameIsSettings(Http2ConnectionHandler.java:353)
    at org.apache.rocketmq.shaded.io.grpc.netty.shaded.io.netty.handler.codec.http2.Http2ConnectionHandler$PrefaceDecoder.decode(Http2ConnectionHandler.java:247)
    at org.apache.rocketmq.shaded.io.grpc.netty.shaded.io.netty.handler.codec.http2.Http2ConnectionHandler.decode(Http2ConnectionHandler.java:453)
    at org.apache.rocketmq.shaded.io.grpc.netty.shaded.io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:510)
    at org.apache.rocketmq.shaded.io.grpc.netty.shaded.io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:449)
    at org.apache.rocketmq.shaded.io.grpc.netty.shaded.io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:279)
    at org.apache.rocketmq.shaded.io.grpc.netty.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
    at org.apache.rocketmq.shaded.io.grpc.netty.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
    at org.apache.rocketmq.shaded.io.grpc.netty.shaded.io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
    at org.apache.rocketmq.shaded.io.grpc.netty.shaded.io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)
    at org.apache.rocketmq.shaded.io.grpc.netty.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
    at org.apache.rocketmq.shaded.io.grpc.netty.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
    at org.apache.rocketmq.shaded.io.grpc.netty.shaded.io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)
    at org.apache.rocketmq.shaded.io.grpc.netty.shaded.io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:166)
    at org.apache.rocketmq.shaded.io.grpc.netty.shaded.io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:722)
    at org.apache.rocketmq.shaded.io.grpc.netty.shaded.io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:658)
    at org.apache.rocketmq.shaded.io.grpc.netty.shaded.io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:584)
    at org.apache.rocketmq.shaded.io.grpc.netty.shaded.io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:496)
    at org.apache.rocketmq.shaded.io.grpc.netty.shaded.io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997)
    at org.apache.rocketmq.shaded.io.grpc.netty.shaded.io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
    at org.apache.rocketmq.shaded.io.grpc.netty.shaded.io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
    ... 1 common frames omitted

It's supposed to be connected properly.Or is there something wrong with my configuration?