It could be because you haven’t put in any numbers for the code. You didn’t specify how much it has to go forward, so that might be an issue. It might also be because you don’t have your Drivetrain as a motor group, so the motors might not be working together.
What coding software are you using? How many motors does you drive have? What are the controls for your drive?
From what I can tell,
VS Code VEX C++
6 motor drivetrain
Split Arcade controls