Sometimes the default DNS fails to resolve Apple's server addresses.
: Apple only "signs" the latest iOS versions. If you are trying to downgrade to an older, unsigned version, 3uTools will fail because Apple's servers are no longer providing those SHSH blobs. You can check current signing status on sites like Repair Drivers i unable to request shsh 3utools fix install
. Apple typically stops signing older versions shortly after a new release, making downgrades to those versions impossible without previously saved SHSH blobs. Use "iTunes Flash" Mode : Within 3uTools, navigate to the Flash & JB tab and try using the iTunes Flash Sometimes the default DNS fails to resolve Apple's
: Verify if the iOS version you are trying to flash is still "signed" by Apple. You can check current signing status on sites like You can check current signing status on sites
