My problem is that sha1 is not secure for my server, and sha256, which encrypts production, is considered secure. Who knows how I get sha256 for sandbox?
PUSH-notifications: How to convert SHA-1 to SHA-256 certificate for sandbox
In the "Create a New Certificate" page, "Services" section choose the "Apple Push Notification service SSL (Sandbox & Production)" entry. That should be a SHA-256 certificate and can be used for both sandbox and production.