Using an old version of 3uTools that lacks support for newer device hardware or firmware protocols.
You are trying to install an iOS version that Apple is no longer "signing" (authorizing). Apple usually stops signing older versions shortly after a new update is released. How To Fix Error Unable To Request Shsh On 3utools When
Before troubleshooting your hardware, check if the iOS version you want to install is actually allowed by Apple. YouTube·Tekzat How to Fix 3uTools 9% ERROR Unable to request SHSH Latest Using an old version of 3uTools that lacks