Then the developer will ask you what troubleshooting you did already and show a detailed server log HEX from the device. And if its different data he will ask for the protocol document..
If it uses the same protocol as other Teltonika devices, it should work on the same port.
I didn't find
Teltonika FMC650
in the Supported Devices - Traccar,I see like all Teltonika devices port is
5027
and I haveFMC130
it works as expected but notFMC650