CAN controllers initialize into error active state. Although this state has the word “error” in the name it doesn’t mean there is an error. It means that the CAN controller can actively send error frames if needed to indicate corrupted data. If the CAN controller is in error passive state then there is a potential problem with the controller or its connectivity and therefore it is not allowed to send error frames.
"FAQ contribution from Embedded Systems Academy, experts in CAN bus. For more information visit www.esacademy.com"