Minecraft shapeshifter

i was downloading the shapeshifter mod for minecraft and a little window opened for me to log in. I typed in the email and the password correctly and the message "cannot connect to minecraft.net." I thought I typed either the email or the password in wrong, and reentered it, making sure it was spelled correctly, but the same message appeared. I then did the same thing with the username yet the exact same message came on screen. (if it helps, I hve windows8) Someone please help I have been trying to get this mod for a year now, including attempting on my old laptop before it broke.