R305 fingerprint not working on hardware serial but works on software serial

I have a r305 sensor and I am trying to integrate it to work on my arduino uno using hardware serial, it seems not to be working but works when I use software serial. I use pins 0 and 1 on the arduino uno. I have used another fingerprint sensor on the same arduino uno, and it works fine using hardware serial. Please help

Do an internet search on the words "how many hardware serial ports arduino uno"

I know it's one, I am trying to use it on the r305 fingerprint but its not working

are you also using it for the Serial monitor? is the baud rate correct? (57600bps?)
show code and wiring.