This certificate has an invalid issuer Apple Push Services in Keychain.

 This isn't issue of development process. its occurs due to expiration of the WWDR intermediate certificate in both System and Login in keychain. You are find the certificate on keychain known as "Apple Worldwide Developer Relations intermediate Certificate" thats release by Apple worldwide Developer Relations Certificate Authority. You are faceting the issue of  "This certificate has an invalid issuer in Keychain." 

Can easily to solve this issue to follow the below steps.

Step 1 : Open Keychain Access.

Step 2 : Go to View >  Show Expired Certificates.

Step 3 : Select "Certificates" category. All Certificate are there which is expired or not.

Step 4 :  Select "Login" and "System" tab, and Search "Apple Worldwide Developer Relation Certificate Authority " and delete it from Keychain.

Step 5 :  Download the new certificate from : https://developer.apple.com/certificationauthority/AppleWWDRCA.cer 

Step 6 :  Go to download folder, and double click on the certificate to install it. You certificate is successfully installed,

Step 7 :  Now go to Keychain and  Search "Apple Worldwide Developer Relation Certificate Authority "  having expiry date year - 2023.


Apple Best answer forum :

Thanks for bringing this to the attention of the community and apologies for the issues you’ve been having. This issue stems from having a copy of the expired WWDR Intermediate certificate in both your System and Login keychains. To resolve the issue, you should first download and install the new WWDR intermediate certificate (by double-clicking on the file). Next, in the Keychain Access application, select the System keychain. Make sure to select “Show Expired Certificates” in the View menu and then delete the expired version of the Apple Worldwide Developer Relations Certificate Authority Intermediate certificate (expired on February 14, 2016). Your certificates should now appear as valid in Keychain Access and be available to Xcode for submissions to the App Store.

Refe : https://forums.developer.apple.com/thread/37208