The is frustrating, but it is almost never a random glitch. In 90% of cases, the cause is one of three things:
The error in 3uTools is usually a sign of a communication breakdown between your PC and Apple’s verification servers. In most cases, it’s because the firmware you’re trying to use is no longer supported. By ensuring you are flashing a "signed" firmware and clearing your network path, you can usually resolve the issue in minutes. 3utools Error Unable To Request Shsh
Think of SHSH blobs as a .