A faulty USB cable or port is causing data packets to drop during the request. How to Fix "Unable to Request SHSH" 1. Check the iOS Signing Status
: An unstable internet connection or a firewall may be blocking the request to gs.apple.com (Apple's signing server).
Sometimes, an outdated program or local security software intercepts the handshake between 3uTools and Apple's validation servers.
If the software fails to pull the SHSH token while your phone is in Normal or Recovery Mode, forcing the device into forces a deeper, hardware-level handshake with the server. Connect Device : Plug your iPhone into your PC.
Before flashing, ensure the iOS version you want to install is still being signed by Apple.