lwip interface send stuck [closed]

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Using the LWIP protocol stack for TCP communication, the device ran as a TCP server for a period of time and found itself stuck in the send interface: send (socket_num, (const void *) msg, len, 0), In addition, after repeated testing, it is easy to reproduce when the device communicates with the PC through the company's internal network (possibly through complex network exchanges, within 1 hour); If the device is directly connected to the PC, it may take a long time to reproduce. What could be the reason for this? The message in case of exception is as follows, but no useful information can be seen:(192.168.1.114 is server)

21190   153.099232  192.168.2.114   192.168.2.36    TCP 79  8080 → 11549 [PSH, ACK] Seq=38152 Ack=10695 Win=2062 Len=25 [TCP segment of a reassembled PDU]
21191   153.099397  192.168.2.36    192.168.2.114   TCP 60  11549 → 8080 [PSH, ACK] Seq=10695 Ack=38177 Win=64010 Len=6
21192   153.105834  192.168.2.114   192.168.2.36    TCP 60  8080 → 11549 [ACK] Seq=38177 Ack=10701 Win=2056 Len=0

21193   153.106100  192.168.2.114   192.168.2.36    TCP 79  8080 → 11549 [PSH, ACK] Seq=38177 Ack=10701 Win=2056 Len=25 [TCP segment of a reassembled PDU]
21194   153.106194  192.168.2.36    192.168.2.114   TCP 60  11549 → 8080 [PSH, ACK] Seq=10701 Ack=38202 Win=63985 Len=6
21201   153.319122  192.168.2.36    192.168.2.114   TCP 60  [TCP Retransmission] 11549 → 8080 [PSH, ACK] Seq=10701 Ack=38202 Win=63985 Len=6
21211   153.620255  192.168.2.36    192.168.2.114   TCP 60  [TCP Retransmission] 11549 → 8080 [PSH, ACK] Seq=10701 Ack=38202 Win=63985 Len=6