use this instead
MyCharacter->CharacterMovement->Velocity += YourDir * YourSpeed;
FVector YourDir = the world space direction to move in
float YourSpeed = the magnitude of the direction vector.
and let us know if that works for you, so we know whether it is related to your use of MoveRight or if it is something else
an example direction:
FVector(0,0,1);
example speed
30000