how to enroll the cpanel iOS Push for Mail APNS cert?

inhi , evry one!

today, we want to setup our cPanel/WHM server to enable IOS Push for Mail support feature, we enrolled on APNS cert in Apple Developer Account and use it to setup this, we got the error:

The SSL certificate update failed.

iOS Push for Mail

(XID xabqa2) The certificate userId field (0.9.2342.19200300.100.1.1) must begin with “com.apple.mail.”

we tried to type the App ID as com.apple.mail. in Apple Developer Account -> new App to deploy one new App, but we got error:

There were errors in the data supplied. Please correct and re-submit.

An App ID with Identifier 'com.apple.mail.qiaokr90.eee' is not available. Please enter a different string.

so, does someone here can help us?

thanks so much!