Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32f1/STM32F101/CAN1/MSR#0x0
master status register
INAK
SLAK
ERRI
WKUI
SLAKI
TXM
RXM
SAMP
RX
https://github.com/modm-io/cmsis-svd-stm32