Does this mean the masters degree will be invalid ? The school was ranked on usnews so I did not think it would be this bad.
No. The Council of Graduate Schools is a nonprofit organization; it has nothing to do with degree validity. While it's true that most reputable graduate schools are members, it does not follow that all non-members are non-reputable.
Moreover, there is no clearcut definition of a "valid" degree in the United States. The closest thing is probably accreditation, and I suspect your school is accredited. But because there is no universally-accepted hierarchy of institutions, employers have to decide for themselves whether they consider your degree meaningful. While the US News & World Report rankings are not perfect, I suspect a degree from any school listed there would be acceptable to pretty much all employers.