Repeated same downlink data

After a class C device joined network,I started to send downlink data.When enqueue a downlink payload no matter confirmed downlink or unconfirmed ,the device is receiving the same downlink data without stop.and then I checked the log of gateway,found that NS is continuously sending the same downlink data without stop. Who can help to solve this?


Below is the log of gateway.
this is for confirmed downlink data,even the device has replied to NS.
2022/03/25 19:30:16.644 DEBUG: [debug_packet_down:1796] Freq:917300000 IMMEDIATE rf_chain: 0 rf_power:14 size: 19 LoRa SF10 CR1(4/5) 125KHZ
2022/03/25 19:30:16.644 DEBUG: [debug_packet_down:1800] A090E21801800000174EBDE00BDD700EF52C19 #
2022/03/25 19:30:18.662 DEBUG: [debug_packet_down:1796] Freq:917300000 IMMEDIATE rf_chain: 0 rf_power:14 size: 19 LoRa SF10 CR1(4/5) 125KHZ
2022/03/25 19:30:18.663 DEBUG: [debug_packet_down:1800] A090E21801800000174EBDE00BDD700EF52C19 #
2022/03/25 19:30:19.207 DEBUG: [debug_packet_up:1700] Freq:918700000 if_chain: 2 tstamp:1256933788 size: 12 LoRa SF12 CR1(4/5) 125KHZ
2022/03/25 19:30:19.207 DEBUG: [debug_packet_up:1704] RSSI: -55.0 SNR: +9.5 (min: +6.8, max:+14.8) count_us:1256933788 payload:
2022/03/25 19:30:19.207 DEBUG: [debug_packet_up:1708] 4090E21801A09700A4F56CA6 #
2022/03/25 19:30:19.791 DEBUG: [debug_packet_down:1796] Freq:918700000 TIMESTAMPED rf_chain: 0 rf_power:14 size: 19 LoRa SF12 CR1(4/5) 125KHZ
2022/03/25 19:30:19.791 DEBUG: [debug_packet_down:1800] A090E21801800000174EBDE00BDD700EF52C19 #
2022/03/25 19:30:22.699 DEBUG: [debug_packet_down:1796] Freq:917300000 IMMEDIATE rf_chain: 0 rf_power:14 size: 19 LoRa SF10 CR1(4/5) 125KHZ
2022/03/25 19:30:22.699 DEBUG: [debug_packet_down:1800] A090E21801800000174EBDE00BDD700EF52C19 #
2022/03/25 19:30:24.718 DEBUG: [debug_packet_down:1796] Freq:917300000 IMMEDIATE rf_chain: 0 rf_power:14 size: 19 LoRa SF10 CR1(4/5) 125KHZ
2022/03/25 19:30:24.718 DEBUG: [debug_packet_down:1800] A090E21801800000174EBDE00BDD700EF52C19 #
2022/03/25 19:30:25.261 DEBUG: [debug_packet_up:1700] Freq:917500000 if_chain: 5 tstamp:1262989340 size: 12 LoRa SF12 CR1(4/5) 125KHZ
2022/03/25 19:30:25.261 DEBUG: [debug_packet_up:1704] RSSI: -53.0 SNR: +7.5 (min: +4.8, max:+12.3) count_us:1262989340 payload:
2022/03/25 19:30:25.261 DEBUG: [debug_packet_up:1708] 4090E21801A0990043281C8B #
2022/03/25 19:30:25.856 DEBUG: [debug_packet_down:1796] Freq:917500000 TIMESTAMPED rf_chain: 0 rf_power:14 size: 19 LoRa SF12 CR1(4/5) 125KHZ
2022/03/25 19:30:25.856 DEBUG: [debug_packet_down:1800] A090E21801800000174EBDE00BDD700EF52C19 #
2022/03/25 19:30:28.758 DEBUG: [debug_packet_down:1796] Freq:917300000 IMMEDIATE rf_chain: 0 rf_power:14 size: 19 LoRa SF10 CR1(4/5) 125KHZ
2022/03/25 19:30:28.758 DEBUG: [debug_packet_down:1800] A090E21801800000174EBDE00BDD700EF52C19 #
2022/03/25 19:30:30.782 DEBUG: [debug_packet_down:1796] Freq:917300000 IMMEDIATE rf_chain: 0 rf_power:14 size: 19 LoRa SF10 CR1(4/5) 125KHZ
2022/03/25 19:30:30.782 DEBUG: [debug_packet_down:1800] A090E21801800000174EBDE00BDD700EF52C19 #
2022/03/25 19:30:31.328 DEBUG: [debug_packet_up:1700] Freq:917300000 if_chain: 4 tstamp:1269055580 size: 12 LoRa SF12 CR1(4/5) 125KHZ
2022/03/25 19:30:31.329 DEBUG: [debug_packet_up:1704] RSSI: -54.0 SNR: +9.8 (min: +7.8, max:+14.8) count_us:1269055580 payload:
2022/03/25 19:30:31.329 DEBUG: [debug_packet_up:1708] 4090E21801A09B0007EFC630 #

this is for unconfirmed downlink data.
2022/03/25 19:48:59.798 DEBUG: [debug_packet_down:1796] Freq:917300000 IMMEDIATE rf_chain: 0 rf_power:14 size: 19 LoRa SF10 CR1(4/5) 125KHZ
2022/03/25 19:48:59.799 DEBUG: [debug_packet_down:1800] 60D243BB0180000017335449CFBB2D41CEA562 #
2022/03/25 19:49:01.818 DEBUG: [debug_packet_down:1796] Freq:917300000 IMMEDIATE rf_chain: 0 rf_power:14 size: 19 LoRa SF10 CR1(4/5) 125KHZ
2022/03/25 19:49:01.818 DEBUG: [debug_packet_down:1800] 60D243BB0180000017335449CFBB2D41CEA562 #
2022/03/25 19:49:05.857 DEBUG: [debug_packet_down:1796] Freq:917300000 IMMEDIATE rf_chain: 0 rf_power:14 size: 19 LoRa SF10 CR1(4/5) 125KHZ
2022/03/25 19:49:05.857 DEBUG: [debug_packet_down:1800] 60D243BB0180000017335449CFBB2D41CEA562 #
2022/03/25 19:49:07.879 DEBUG: [debug_packet_down:1796] Freq:917300000 IMMEDIATE rf_chain: 0 rf_power:14 size: 19 LoRa SF10 CR1(4/5) 125KHZ
2022/03/25 19:49:07.879 DEBUG: [debug_packet_down:1800] 60D243BB0180000017335449CFBB2D41CEA562 #
2022/03/25 19:49:09.898 DEBUG: [debug_packet_down:1796] Freq:917300000 IMMEDIATE rf_chain: 0 rf_power:14 size: 19 LoRa SF10 CR1(4/5) 125KHZ
2022/03/25 19:49:09.898 DEBUG: [debug_packet_down:1800] 60D243BB0180000017335449CFBB2D41CEA562 #
2022/03/25 19:49:11.922 DEBUG: [debug_packet_down:1796] Freq:917300000 IMMEDIATE rf_chain: 0 rf_power:14 size: 19 LoRa SF10 CR1(4/5) 125KHZ
2022/03/25 19:49:11.923 DEBUG: [debug_packet_down:1800] 60D243BB0180000017335449CFBB2D41CEA562 #
2022/03/25 19:49:13.941 DEBUG: [debug_packet_down:1796] Freq:917300000 IMMEDIATE rf_chain: 0 rf_power:14 size: 19 LoRa SF10 CR1(4/5) 125KHZ
2022/03/25 19:49:13.941 DEBUG: [debug_packet_down:1800] 60D243BB0180000017335449CFBB2D41CEA562 #
2022/03/25 19:49:15.961 DEBUG: [debug_packet_down:1796] Freq:917300000 IMMEDIATE rf_chain: 0 rf_power:14 size: 19 LoRa SF10 CR1(4/5) 125KHZ
2022/03/25 19:49:15.962 DEBUG: [debug_packet_down:1800] 60D243BB0180000017335449CFBB2D41CEA562 #
2022/03/25 19:49:17.972 DEBUG: [debug_packet_down:1796] Freq:917300000 IMMEDIATE rf_chain: 0 rf_power:14 size: 19 LoRa SF10 CR1(4/5) 125KHZ
2022/03/25 19:49:17.972 DEBUG: [debug_packet_down:1800] 60D243BB0180000017335449CFBB2D41CEA562 #
2022/03/25 19:49:19.995 DEBUG: [debug_packet_down:1796] Freq:917300000 IMMEDIATE rf_chain: 0 rf_power:14 size: 19 LoRa SF10 CR1(4/5) 125KHZ
2022/03/25 19:49:19.995 DEBUG: [debug_packet_down:1800] 60D243BB0180000017335449CFBB2D41CEA562 #
2022/03/25 19:49:22.014 DEBUG: [debug_packet_down:1796] Freq:917300000 IMMEDIATE rf_chain: 0 rf_power:14 size: 19 LoRa SF10 CR1(4/5) 125KHZ
2022/03/25 19:49:22.014 DEBUG: [debug_packet_down:1800] 60D243BB0180000017335449CFBB2D41CEA562 #
2022/03/25 19:49:24.031 DEBUG: [debug_packet_down:1796] Freq:917300000 IMMEDIATE rf_chain: 0 rf_power:14 size: 19 LoRa SF10 CR1(4/5) 125KHZ
2022/03/25 19:49:24.031 DEBUG: [debug_packet_down:1800] 60D243BB0180000017335449CFBB2D41CEA562 #
2022/03/25 19:49:26.052 DEBUG: [debug_packet_down:1796] Freq:917300000 IMMEDIATE rf_chain: 0 rf_power:14 size: 19 LoRa SF10 CR1(4/5) 125KHZ
2022/03/25 19:49:26.052 DEBUG: [debug_packet_down:1800] 60D243BB0180000017335449CFBB2D41CEA562 #
2022/03/25 19:49:28.091 DEBUG: [debug_packet_down:1796] Freq:917300000 IMMEDIATE rf_chain: 0 rf_power:14 size: 19 LoRa SF10 CR1(4/5) 125KHZ
2022/03/25 19:49:28.091 DEBUG: [debug_packet_down:1800] 60D243BB0180000017335449CFBB2D41CEA562 #
2022/03/25 19:49:30.114 DEBUG: [debug_packet_down:1796] Freq:917300000 IMMEDIATE rf_chain: 0 rf_power:14 size: 19 LoRa SF10 CR1(4/5) 125KHZ
2022/03/25 19:49:30.114 DEBUG: [debug_packet_down:1800] 60D243BB0180000017335449CFBB2D41CEA562 #
2022/03/25 19:49:32.197 DEBUG: [debug_packet_down:1796] Freq:917300000 IMMEDIATE rf_chain: 0 rf_power:14 size: 19 LoRa SF10 CR1(4/5) 125KHZ
2022/03/25 19:49:32.197 DEBUG: [debug_packet_down:1800] 60D243BB0180000017335449CFBB2D41CEA562 #

Most likely the gateway is not sending the ACK to the network server that it received (and scheduled) the downlink packet. Thus the server re-sends it