STM32F103 USART3 RX problem not triggering interrupt while data comes to pin

Hello,

I work on the STM32f103.

For the project I need to comunicate through USART but here is the problem;

I can transmit everything to my computer but whenever my PC replies back, nothing happens.

Rx interrupt has been enabled but I'm never going into the interrupt routine.

Has anyone already been facing this kind of problem?