Thank you very much.
ipconfigSOCK_DEFAULT_SEND_BLOCK_TIME is set 2000.
\FreeRTOSIPConfig.h(71): #define ipconfigSOCK_DEFAULT_SEND_BLOCK_TIME (20000)
Then by FreeRTOS_setsockopt() is set FREERTOS_SO_RCVTIMEO.
I ask because your FreeRTOS tick rate is set to 16kHz and timeouts are set in ticks. We demo our libraries with a 1kHz tick or slower. The default timeout we provide in our configs is 5000 ticks, or 5ms at 1kHz. 5000 ticks in your case would be 312.5us at 16kHz.
I was also concerned about this tick rate setting.
This tick rate is recommended to be 1 kHz, and it should not be faster.
Is this setting causing the error?