I have to signal my mobileconfig file to indicate verified，i exploit Free SSL Certificates from CloudFlare，However nonetheless say not verified，the place is the issue？

openssl smime -sign -in a.mobileconfig -out a_signed.mobileconfig -signer ssl.pem -inkey ssl.key -certfile ssl.pem -outform der -nodetach

The place else can I get a certificates that may be verified?