I sent downlink message to my class c node.
But, I got the message from my node which is need to 6 seconds and more.
I think unreasonable for class C node and loraserver.
so, I check lora server log and setting. I discover some error from mosquitto or fluentd DB.
I attach the error picture in this post.
P.s. I guess some component or wrong version for Lora server.