I saw a poster signed by the cast of Stranger Things, but it looks far too cheap to be real. They said their COA was from Status Authentication. I have never heard of the COA before. This is the website:
I don't think that is real. It's an obvious forgery in my opinion.
Learning how to buy genuine autographs isn't that hard, Cameron. Take time to learn more about autographs before you buy. A few months if you can wait. Your collecting will be so much more fun and successful if you do.