How can I fix this issue?
You get that if you're trying to install the grader when you already have it installed. You install it once and then you can grade all the labs. No need to install again and in fact, you can't.
You get that if you're trying to install the grader when you already have it installed. You install it once and then you can grade all the labs. No need to install again and in fact, you can't.