App Store Login : ID Password Incorrect even if correct login credentials are entered

I have old macbook 2008 (Late) edition. I just formatted it to add new SSD and El capitan in it. I have SNOW LEOPARD DVD so I just used to to boot. But just to check if the process is smooth, i tried the installation on old HDD which came with macbook. I have used this DVD around 3 years back and it went smoothly. But now when I am trying to install Maverick OSX via App Store, its not allowing me to do it. I tried both paths.

FIRST: Installed snow leopard and then tried to open APP STORE in it. But it didnt allow me to connect to APP STORE and gave a message that ID/Password is wrong. But at the same time I got 6 digit pin on my iPhone. Now there is no textbox on APP STORE < SNOW LEOPARD> where I can fill ID + PASSWORD + 6 digit PIN . SO here I am stuck.

SECOND: After formatting HDD, used RECOVERY mode. Atleast here I am getting an option to upgrade to MAVERICK. When I select that it asks me to select the hard disk but again it asks my APPLE ID credentials. So Same issue. it didnt allow me to connect to APP STORE and gave a message that ID/Password is wrong. But at the same time I got 6 digit pin on my iPhone.

My macbook is in very great condition and i have bought SSD to increase its performance. But now I am stuck.

Such issue is not faced by me on my iPhone SE 2016

Plz help me to save my macbook.