Node does not reconnect to the gateway

Hi, i have a question. I’m sorry if it’s a dumb question since i;m new to LoRaWAN. I have setup my node to send data to the gateway and it works perfectly fine. I powered up the node using computer but the problem is whenever i disconnect the device and reconnects it back, it does not send new data. what should i do to fix this problem. Really appreciate your help. Thanks!

Are you using ABP or OTAA? If you are using ABP and your node restarts with the FCNT parameter at 0 every time you power it up, that would explain it.

I’m using ABP. The fcnt starts with 0. How do i fix this problem to make sure that it does not reset?