Interfacing CANSPI with problems
When troubleshooting serial buses, an oscilloscope is invaluable. If you don't have a lab grade instrument, pick up a simple, inexpensive USB scope. There are also inexpensive CAN/SPI diagnostic modules available in USB format.

It is always a good practice when troubleshooting serial bus problems, to significantly reduce the bus speed. This not only makes it easier to spot problems with a scope, but the effect of parasitics is dramatically reduced. Once you getting it working at low speed, you can raise the frequency to observe and isolate any changes.