Unable to purchase at iTunes

Well, we would need a whole lot of additional information, as there may be many situations that would cause this.

Here are a few examples:

• Have you changed country or region recently?
• Have you changed your Apple ID or password?
• Have you changed your credit information?
• Have you changed the Apple ID that uses iTunes on this computer?

Assuming you were formerly able to make purchases, carefully review what changed since that time.

I have changed my password and also my card info. So what does that mean ?