# TTN gateway does not send downlink **URL:** \ **Category:** Gateways\ **Created:** [October 9, 2018, 1:21pm UTC](https://www.thethingsnetwork.org/forum/t/ttn-gateway-does-not-send-downlink/18594 "2018-10-09T13:21:41Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![mathieu\_pouillot](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/mathieu_pouillot/32/35697_2.png) [@mathieu\_pouillot](https://www.thethingsnetwork.org/forum/u/mathieu_pouillot)\ **Post date:** [October 9, 2018, 1:21pm UTC](https://www.thethingsnetwork.org/forum/t/ttn-gateway-does-not-send-downlink/18594/1 "2018-10-09T13:21:41Z")
I have a strange behavior. On my 868 Mhz TTN gateway, it seems no downlink is sent from the gateway. I connect a spectrum analyser on it, and I see nothing from it. I have the log at network level : ![image](https://www.thethingsnetwork.org/forum/uploads/default/original/3X/6/5/65644cfb71fc9d7bac4b083f7717936b125a13f7.png) , but nothing on RF. I have just one sensor connected to the gateway and the traffic is very low, so the dutycyle has to be ok. Have you an idea from where com from? best regards, Mathieu ---
**Author:** ![BoRRoZ](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/borroz/32/44234_2.png) [@BoRRoZ](https://www.thethingsnetwork.org/forum/u/BoRRoZ)\ **Post date:** [October 9, 2018, 1:35pm UTC](https://www.thethingsnetwork.org/forum/t/ttn-gateway-does-not-send-downlink/18594/2 "2018-10-09T13:35:16Z")
what sensor do you use… OTAA / ABP ? I don’t see this gateway connected can your sensor join the network… please show the connection ---
**Author:** ![arjanvanb](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/arjanvanb/32/46626_2.png) [@arjanvanb](https://www.thethingsnetwork.org/forum/u/arjanvanb)\ **Post date:** [October 9, 2018, 4:13pm UTC](https://www.thethingsnetwork.org/forum/t/ttn-gateway-does-not-send-downlink/18594/3 "2018-10-09T16:13:17Z")
Any chance the latency on the internet connection is high, and the downlink packets arrive at your gateway too late? (Using a serial port monitor, I got one [LORA: TXPKT failed, too late!](https://www.thethingsnetwork.org/forum/t/getting-lora-txpkt-failed-too-late-in-ttn-gateways-serial-output/18206) today, but that’s often caused by problems in the backend, not in my connection.) Is the gateway registered to the router closest to you? (So, `ttn-router-eu` for France.) > [@mathieu\_pouillot](#): > > the traffic is very low Meanwhile your gateway [has forwarded](http://noc.thethingsnetwork.org:8085/api/v2/gateways/gateway-watteco1) ~~112,350~~ ~~112,439~~ ~~112,455~~ 112,475 uplinks, though those might not all have been sent by your own node. Still then, if TTN tells a gateway to send a downlink, it should indeed do so. ---
**Author:** ![azazeal](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/azazeal/32/31690_2.png) [@azazeal](https://www.thethingsnetwork.org/forum/u/azazeal)\ **Post date:** [October 10, 2018, 5:22am UTC](https://www.thethingsnetwork.org/forum/t/ttn-gateway-does-not-send-downlink/18594/4 "2018-10-10T05:22:59Z")
You mention TTN gateway, but just in case, is this actually a custom gateway running the multi packet forwarder – if yes, are you using the UDP transport (rather than TTN transport?). I had some very similar issues to this where the downlinks were sent and received by the packet forwarder and also scheduled to the concentrator on time, but did not seem to be emitted. ---
**Author:** ![mathieu\_pouillot](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/mathieu_pouillot/32/35697_2.png) [@mathieu\_pouillot](https://www.thethingsnetwork.org/forum/u/mathieu_pouillot)\ **Post date:** [October 15, 2018, 10:36am UTC](https://www.thethingsnetwork.org/forum/t/ttn-gateway-does-not-send-downlink/18594/5 "2018-10-15T10:36:26Z")
No it is not the latency on the internet connection. I have 5 others gateway (kerlink, multitech, gemteck,…) which have no problem. And the problem is already on the first frame : join request which have an answer after 5 sec… I have several devices (we are lorawan devices maker) which speak on a lot of gateway, operator, so it is true we have a lot of traffic but not specific to the ttn gateway… ---
**Author:** ![mathieu\_pouillot](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/mathieu_pouillot/32/35697_2.png) [@mathieu\_pouillot](https://www.thethingsnetwork.org/forum/u/mathieu_pouillot)\ **Post date:** [October 15, 2018, 10:37am UTC](https://www.thethingsnetwork.org/forum/t/ttn-gateway-does-not-send-downlink/18594/6 "2018-10-15T10:37:52Z")
it is ttn gateway, this one: [https://uk.farnell.com/the-things-network/ttn-gw-868/the-things-gateway-eu/dp/2675813](https://uk.farnell.com/the-things-network/ttn-gw-868/the-things-gateway-eu/dp/2675813) ---
**Author:** ![mathieu\_pouillot](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/mathieu_pouillot/32/35697_2.png) [@mathieu\_pouillot](https://www.thethingsnetwork.org/forum/u/mathieu_pouillot)\ **Post date:** [October 15, 2018, 10:44am UTC](https://www.thethingsnetwork.org/forum/t/ttn-gateway-does-not-send-downlink/18594/7 "2018-10-15T10:44:49Z")
when I connect a logger through uart connection;, I receive this: 12:33:48.300\> MQTT: Sending UPLINK OK 12:33:48.754\> MON: SYS Stack size: 2851 12:33:48.754\> MON: TCPIP Stack size: 3787 12:33:48.754\> MON: APP Stack size: 3294 12:33:48.754\> MON: LoRa Stack size: 3857 12:33:48.754\> MON: heap usage: 278KB (279KB), free: 61KB 12:33:49.567\> MQTT: Received DOWNLINK _ **12:33:49.567\> LGMD:Command, cmd: 0x32, size: 59** _ _ **12:33:50.754\> LGMD:Timeout on cmd: 0x32** _ 12:33:55.134\> LGMD:LORA: Accepted packet So the sx1272 seems to be busy and we receive a Time Out answer… Is my problem should be that the Downlink is not prioritary on Uplink reception ? ---
**Author:** ![mathieu\_pouillot](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/mathieu_pouillot/32/35697_2.png) [@mathieu\_pouillot](https://www.thethingsnetwork.org/forum/u/mathieu_pouillot)\ **Post date:** [October 15, 2018, 10:46am UTC](https://www.thethingsnetwork.org/forum/t/ttn-gateway-does-not-send-downlink/18594/8 "2018-10-15T10:46:10Z")
i’m in OTAA, the sensor doesn’t join the network because the join accept is never sent to my sensor… ---
**Author:** ![arjanvanb](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/arjanvanb/32/46626_2.png) [@arjanvanb](https://www.thethingsnetwork.org/forum/u/arjanvanb)\ **Post date:** [October 15, 2018, 3:24pm UTC](https://www.thethingsnetwork.org/forum/t/ttn-gateway-does-not-send-downlink/18594/9 "2018-10-15T15:24:39Z")
> [@mathieu\_pouillot](#): > > join request which have an answer after 5 sec… I understand that latency is not a problem, so just for future reference: the fact that a Join Accept’s RX1 is as long as 5 seconds (where a regular downlink’s RX1 is just 1 second) is not relevant, as TTN will probably just wait longer before sending the downlink to a gateway.