1. Check please your modification of TST100 (must be CAN);
2. On the settings in CAN section select protocol-type of your can-bus line. If your object work on the J1939 protocol - select this. If your object work on the other type of the can messages (Special IDs) - please, select "Manual CAN" and input ID values and Data Mask, which you need read from the can-bus. Do not forget about right speed of the can-bus line.
More info about Manual CAN you can get from the wiki: https://wiki.teltonika-mobility.com/view/TFT100_Manual_CAN_settings
TFT100 be able to communicate directly with CAN-Line.