HAL UART HAL_UART_Receive Timeout
Something that tripped me up in the past is the hardware TX/RX connection and voltage levels.
Check that RX pins goes to TX pins (do not get confused with DB9 serial connections).
Do ensure that you are not pushing real RSR232 signals to the ARM pins, they will pop'n'fry.
I suggest a "loopback" connection first, TX to RX on same UART. Just to get going.