That is not a gateway, that is a Dual Channel Packet Forwarder that can only hear two channels at a time.
Whereas a gateway can hear on 8 channels and detect transmissions on any of the Spreading Factors at the same time - so there are 48 possibilities that the device can transmit on and your DCPF can only hear 2 of them.
So your device transmits a join request but your DCPF can’t transmit the answer as it won’t understand the request correctly. Until the device joins, it will never be able to uplink. Even if by some statistical co-incidence of channel selection, it would still suffer dropped uplinks as the gateway won’t be able to hear the majority of the frequency & SF combinations.
As this will cause similar disruption to other users of the community TTN, please disconnect your DCPF immediately.
PS, Dragino make it clear on their website that this item is not LoRaWAN compliant.