Iphone 7: Send enrollment PUSH not displaying

Hello. I completed the procedure to download the final certificate from Apple but in the Devices list my Iphone 7 doesn’t show the “Send enrollment PUSH” option. Also, after installing and signed in for the first time, I cannot sign in again to my Prey app on the phone as it says “Couldn’t add your device” as the devices limit has been reached. I removed the device on my PC and reinstalled the app on the phone multiple times but no luck. Can someone help please?