Sometimes the default DNS fails to resolve Apple's server addresses.
Sometimes, security software blocks 3uTools from sending the request to Apple’s servers.
Before fixing the issue, it is important to understand what is happening. i unable to request shsh 3utools fix install
SHSH Blobs (Signature HaSH) are digital signatures that Apple uses to control iOS installations. When you try to install an iOS version, Apple’s servers must "sign" the request.
The error "Unable to request SHSH" essentially means 3uTools knocked on Apple’s door to ask for permission to install the firmware, and Apple (or the Cydia server) said "No," or the request failed due to network issues. Sometimes the default DNS fails to resolve Apple's
If you have tried all fixes and the firmware is unsigned, you have two realistic options:
“The ‘Unable to request SHSH’ error in 3uTools’ Fix Install feature is primarily due to Apple’s signing window closure for the target iOS version. Without previously saved SHSH2 blobs matching the device’s ECID, a valid signature cannot be retrieved, making restore impossible unless advanced bootchain exploits are available (none for modern iOS).“ Click OK and restart 3uTools
If you need a full academic-style breakdown (intro, related work, analysis, fix) written as a short paper, I can generate that for you. Let me know.