Adding a coupon code destroyed my site

Hello. I am using 3.5.0.8. I have no way to explain it, but my site was working fine for months, and I just added a coupon code 5 minutes ago, and my entire site got destroyed. All content is now private. I cannot log in as a user. Clicking log out does nothing. Every page leads to a protected page. All I can do is log into the Dashboard as an admin, but I cannot do anything. Can you try and duplicate this? All I did was add a coupon code and it destroyed my entire site. I did nothing else other than add that coupon code. So it must be the coupon code that took down my site. But I don't know why. Can you please help? Is this a bug in 3.5.0.8? I granted access for support. I have never seen anything like this happen to a website just by adding a coupon code.