American visa was refused once, can I apply for a second visa?

First of all, don't worry too much about being refused a visa for the first time. Doesn't mean you can't sign it again after being rejected. These are all nonsense, and when to sign again after rejection has nothing to do with time. The key is whether your binding force is stronger than last time. If the binding force is more than last time, you can sign it again at any time.

If you don't change anything, that is, the binding force remains the same as last time, even if you sign in 10, the result will still be rejected, so when you can sign again after being rejected has nothing to do with the time, mainly depending on whether your binding force has increased compared with last time. As long as you add it, you can sign it again right away.

In fact, as long as all your information is adjusted and improved and the overall binding force is improved next time, the possibility of passing is still very high.