Able to send uplink data only once at first attempt

When I run my Arduino Code very first it is able to send uplink data successfully to app server but then for every uplink data it is not possible to send it although my serial monitor of Arduino says successful transmission. I have tried that same code with TTN network there it is working fine but when it comes to LoRa Server there is an issue.And also for every unconfirmed uplink data there is unconfirmed downlink data down.Please help me with this issue.I have tried a lot but no any solution found.It will be more helpful if you access my PC using Team Viewer and solve the issue as soon as possible.

Please check your LoRa Server logs.

The Log is only showing one uplink packet received but my device is continuously transmitting uplink packet but server it is not seen on the log and only publishing gateway stats packet.Please look into my issue asap.