I am currently encountering an issue: when creating a new push certificate on the Apple Push Notification Certificates portal, I am required to generate a signature beforehand. Could you please explain the specific rules for this signature and how I should go about generating it? (I previously attempted to generate the certificate using the following command—openssl req -new -key mdm_push.key -out mdm_push.csr—but after uploading it, I received an error indicating an incorrect format.)
!