Do you have a paid Developer Program account, or are you working with Xcode's free provisioning?
Which version Xcode are you using, on which macOS?
>am trying to create the certificates
What process are you using? Which certificates, exactly? ...just the high points, thanks.
Thanks for your reply,
1. My account is paid of developer program,
2.Use Version 10.2.1 of xcode and use Macos Mojave 10.14.5
3.I am trying to create Apple Development certificates and it does not work
add a screenshot of my problem https://ibb.co/4VRWGwS, thanks.