Welcome! It appears you did not read the CAN specifications. From what I can determine it is working the way it should. The CAN protocol requires an in-message acknowledge, if it does not receive it will try a bunch of times and fail. It appears you used Cory Fowler's library, in there there is also a receive module. You need that on the bus along with the appropriate termination resistors. Be sure the bus is at least 1 meter in length. If you look at the message on your scope it will look just fine but at the acknowledge point the transmitter is sending a recessive bit, the receivers place a dominate bit on the buss during that time slot.