What's the maximum bitrate of the MKR CAN shield

I have a problem when trying to develop communication between two Arduino MKR CAN shields.
Both shields are driven by the Arduino MKR ZERO

They work correctly when the bit rate is under CAN_250KBPS, but when I set the bit rate to CAN_500KBPS and CAN_1000KBPS, I cannot receive anything from the receiver.

My ideal plan is to set up the communication at CAN_1000KBPS, so I am wondering if 250KBPS is the maximum bitrate of the MKR CAN shield or if there are any methods to increase its bit rate?

I’d also like to know a solution. I’m also not able to receive nor send CAN frames using 1 mbps.

I’m using the library from sandeepmistry. On their github page someone gives some optimizations for the SPI communication here:

Please try. As soon as I can connect my MKR to a CAN bus again I will also.

engeen:
I'd also like to know a solution. I'm also not able to receive nor send CAN frames using 1 mbps.

I'm using the library from sandeepmistry. On their github page someone gives some optimizations for the SPI communication here:
MCP2515 bandwidth issues at 500K and 1Mbps -> SPI command optimizations · Issue #31 · sandeepmistry/arduino-CAN · GitHub

Please try. As soon as I can connect my MKR to a CAN bus again I will also.

I finally made my system work at 1MBPS. It was the problem with the clock instead of the bitrate.
As the transmitter, we need to set the frequency to 16MHZ by using mcp2515.setBitrate(CAN_1000KBPS,MCP_16MHZ); or mcp2515.setBitrate(CAN_1000KBPS);
As the receiver, it needs to be set to mcp2515.setBitrate(CAN_1000KBPS,MCP_8MHZ).