TCP connect very slowly, maybe ARP problem ?

[awander]

I encountered a TCP connect problem:
* I startup a TCP Socket Server at ESP32
* When I try to connect to the ESP32 from PC(Windows), it may cost more than 30s to establish the connection !
* If I ping the ESP32 continuously with a command "ping 192.168.0.xxx -t" on PC(Windows), then the connection can be established very quickly in few seconds !

While checking ARP table of the Windows ("arp -a"), I can find a dynamic ARP record of the ESP32.
If I stop the ping command and wait about 50 seconds, I can still see the ARP record of the ESP32.
STRANGE: But when I try to connect to the ESP32 again, I find that: the ARP record of the ESP32 is disappeared quickly !!! And the connection is blocked for long time to establish !!!

I have no idea how to resolve this problem now, can anybody give me some advises ?
Thanks !