iTunes error, "Software for this iPhone is not currently available"

I have an iPhone 6 that I am trying to restore through iTunes in DFU mode but it is not working. When i click restore, it says "Software for this iPhone is not currently available, Make sure you have the latest version of iTunes and try again". So i do have the latest version of iTunes, i made sure of it. Also my computer is running the latest version of windows 10 and there are no updates for it. I also tried to download an IPSW and hold shift and click restore but then that gives me another message "The iPhone could not be restored because the firmware file is not compatible". I downloaded the right IPSW and i downloaded different ones for the right phone and they are all still being signed by apple, but it is not working. Ive even tried it on a Mac and another Windows computer but im still having that same message. Please i need help restoring this phone, i dont know how to restore it through itunes without getting an error.