Second red flag...It's always a scam if someone tries to pay with a check outside of Upwork.

You either need to get paid hourly or through milestones on Upwork.

Upwork also takes out a fee. I think it's 20% but I don't remember.

Places like Upwork are filled with scams and they often offer decent rates but they won't pay anything. It will actually cost you money with the check scam.