Vehicle Toolbox - CAN bus

Hi everyone, I am experimenting with a data transfer on the CAN bus with the help of Vehicle Toolbox in Simulink. With a Baudrate equal to 125 kBd/s everything works fine, with 250 kBd/s my Vector CANcase Xl shows an error sometimes and with the speed of 500kBd/s (actually the intended one), the transmission does not work at all. Could it possibly lie on the Simulink settings or is it more a message-dependent problem? I use fixed size step with step size of 0.05 (the actual data are loaded in Matlab workspace from other program with step size of 0.1, so I have a good sampling factor). Anything with a good knowledge of CAN Message format and related problems?

I use standard chain: CAN PACK-Transmit-Receive-Unpack (Configuration)

Thank you in advance M