LP-CC2652R7: Why can't the coap in the temperature sensor be sent to the coap server in the border router?

Tool/software:

SDK: simplelink_cc13xx_cc26xx_sdk_6_41_00_17

Sample program: temp_sensor_LP_CC2652R7_tirtos7_ticlang

Background:
The host and the border router are on the same wifi, the temperature sensor is connected to the border router, and the Espressif coap_server is established on the border router to receive the value sent by the temperature sensor

Question:
Why can't the coap post in the temperature sensor example be sent to the Espressif coap_server example server?

Trial process:
I tried ff02::1 and the server's IPV6 address as the sending address, but I didn't get any feedback from the coap server.

I wrote a program on the host using the aiocoap library to get the value in the temperature sensor, and it succeeded (using the IPV6 address of the temperature sensor). I also tried to use get to get the value of the coap_server on the border router and use post to push the value, which also succeeded. But I don't know why the coap in the temperature sensor cannot be sent to the server in the border router
This is the python code I wrote:

import logging
import asyncio
import time

from aiocoap import *

# logging.basicConfig(level=logging.INFO)
count = 0


async def main():
    global count
    
    sensor_address = "fd01:2c48:84a3:1:ef0f:45ea:99dc:ca90"  
    resource_path = "/tempsensor/temperature" 

    protocol1 = await Context.create_client_context()

    request = Message(code=GET, uri=f"coap://[{sensor_address}]{resource_path}")

    try:
        response = await protocol1.request(request).response

    except Exception as e:
        print("Failed...")
        # print(e)
    else:
        print("%d: %r" % (count, response.payload))
        count += 1


if __name__ == "__main__":
    while 1:
        time.sleep(1)
        asyncio.run(main())