By methodically working through the solutions in this guide—from DNS changes to DFU mode and local SHSH flashing—you will likely resolve the error and get back to managing your iDevice with confidence. Remember: patience and the right troubleshooting sequence are your best tools.
Apple has stopped supporting this version. 3utools Error Unable To Request Shsh
Switch to an original Apple USB cable and try a different USB port (preferably on the back of a desktop PC). Check Network: By methodically working through the solutions in this
: A local firewall, antivirus software, or custom hosts file is blocking 3uTools from communicating with Apple’s verification servers. no SHSH blob is issued
If Apple has stopped signing that iOS version, no SHSH blob is issued, and the installation fails. Common Causes of the "Unable to Request SHSH" Error