: Ensure your computer has a stable internet connection. Firewall or antivirus settings can sometimes block the request to gs.apple.com (Apple's signing server).
If the automated request continues to fail, you can try manually retrieving an AP Ticket (SHSH blob): how to fix error unable to request shsh on 3utools when top
Sometimes, putting your device into DFU (Device Firmware Update) mode before attempting to request SHSH can help. : Ensure your computer has a stable internet connection
: Go to the Toolbox tab and select iTunes Utility , then click Repair Driver to ensure the connection between your PC and iPhone is optimal. Manual SHSH Workaround (sh.host) how to fix error unable to request shsh on 3utools when top
Newer versions like specifically include fixes for SHSH request errors. 3. Switch to "iTunes Flash" Mode