Ensure AppSync Unified is properly installed and that your device has been rebooted after the Cydia installation. Double-check that the IPA is strictly a 32-bit application compatible with iOS 7.
Double-check that your device's date and time are set correctly. Outdated system times throw off certificate handshakes. ipa files for ios 712 patched
You must jailbreak your device (usually using Pangu or similar tools for 7.1.2) to make use of AppSync and file managers. Ensure AppSync Unified is properly installed and that