Server does not log anything about the connection

I have a chinese device that I can connect it to other servers as tk-103 where I had to remove the first 4 digits from the IMEI and it shows on the map, Also on a debug server it sends data as a tk-103, But on Traccar I cannot get any log data from the unit .

I tried to test mobile device data and it shows on log file , but for this device, I cannot get anything.
I have changed the port many times but with no luck.
Any idea about this problem ?

Please read this page:

https://www.traccar.org/ports-for-tk-gt-and-other-gps-devices/

If it still doesn't work, please provide some log fragment with data from your device.