PySerial write() hangs after sending more than once

Question

I am using a Nucleo-f303re board and I currently have the board setup for USB. Communication is sent/received using a Virtual COM Port connection. The board is being using as a waveform generator. I am sending a frequency value to the STM32 and it is taking that value to be used in a function.

When I run the python code, enter a value, the frequency output is successfully changed and is confirmed via oscilloscope. Also, the program, successfully receives the sent data back. This all works once, the issue is when I enter a second value. The program then hangs after sending with no errors. On the MCU side, the frequency does not change.

import serial


def feeler(ser):
while True:
    # Prompt the user to input a frequency value
    freq_str = input("Enter frequency value (Hz) or 'q' to quit: ")

    if freq_str.lower() == 'q':
        break

    # Check if the input is a valid integer
    try:
        freq = int(freq_str)
    except ValueError:
        print("Invalid input")
        continue

    # Send the frequency value to the STM32 over serial port
    send_freq(ser, freq)


def send_freq(ser, freq):
try:
    # Convert the frequency value to a byte string and send it over serial port
    freq_bytes = freq.to_bytes(2, byteorder='little')
    print(f"Sending frequency: {freq}")
    ser.write(freq_bytes)
    response = ser.read(2)
    print(f"Received response: {response}")
    # Convert the received bytes to an integer value
    freq_received = int.from_bytes(response, byteorder='little')

    # Print the received frequency value
    print("Received frequency:", freq_received)

except serial.SerialException:
    print('Failed to communicate with the device')


if __name__ == '__main__':
try:
    ser = serial.Serial('COM6', 115200, timeout=1)
    feeler(ser)
except serial.SerialException:
    print('Failed to open serial port')
finally:
    ser.close()

In the first test I entered "100" and in the second test I entered "200." Before digging into the MCU code, I wanted to verify if the python code was correct.