Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32f1/STM32F101/UART4/CR3#0x0
UART4_CR3
Error interrupt enable
IrDA mode enable
IrDA low-power
Half-duplex selection
DMA enable receiver
DMA enable transmitter
https://github.com/modm-io/cmsis-svd-stm32