MPU6050 accelerometer not working

Hi, we use MPU6050 for accel and gyro, when I do rotation test on each axis, gyro is working fine, but accel only noise data. Does anybody has this
problem before? did I miss anything to configure accel? or is it hardware
issue?

Here's what I configured for MPU6050:

0x6B, 0x09 // Power Register (Register Address, Value) Value
0x68, 0x07 // Reset Register (Register Address, Value) Value
0x1B, 0x08 // GYRO_CFG Register (Register Address, Value) Value: +-500 deg
0x1C, 0x09 // ACCEL_CFG Register (Register Address, Value) Value: +-4g


Thanks

Dong