What dose server error 400(try again later) mean in deployment?

I try to deploy my app but keep getting this:
Error deploying application: Server error 400 (please try again later)
and I’m not sure how to fix this problem.

Hi @zhaozhao we need a bit more information if you want help from us. Where are you trying to deploy to? What are you using to deploy? What does your deploy script look like?