How to fix Game Center on iOS 7.1.2
1: you need to get all of the Certificates from here: https://tlsroot.litten.ca
2: Next you need to install the app called Filza, navigate to the directory: "/var/mobile/Library/Preferences"
3: look for any folders that have anything EXTERMELY similar to "purplebuddy", "accountsettings", "itunesstored", "storeservices", "iTunesStore" and "gamed" in the name.
4: delete the files or move them after, next go to the directory: "/var/mobile/Library/Caches" and repeat the same progress, except instead of folders, its .plist files.
5: after doing that please go to the directory: "/var/mobile/Library/" and repeat the same progress, it should only be folders and be very careful.
6: after you deleted/moved those files, you need to either reboot or respring, go through the Setup screen like normal.
7: once you get to the Apple ID screen, make sure you sign in correctly since you have the Certificates.
8: for the final result, open game center and see if it loaded, if it did not load then please attempt again.:
This tutorial is by @fifiIsAwesum. @2024