My friend tried restoring the iPhone, but the device displayed iTunes error 21. He tried again and again with the same result every time. How to fix iTunes error 21 easily?
The main cause behind the error 21 is that the iTunes is not authenticated to download the files as it tries to retrieve them. Dr. Fone toolkit is the best option for the IOS system recovery. You can restart and update iTunes. Turn off the Anti-Virus, remove any unnecessary USB devices, and check the sensor cable as well. Update each software in your phone. Recovery mode also provides the best alternative as well.
