We're excited to announce that we've fully migrated the Xbox Forums to their new home, here on the Microsoft Community forums!
As of today, going to forums.xbox.com will redirect you here to the Xbox area of the Community forums. We've moved all of your existing threads over so you can continue and start conversations with the new forums experience.
We sincerely appreciate the feedback you have provided over this transition and can't wait for you to check out the new Xbox Forums!
I also had this same problem.. the following might be one of the reasons for your problem.
1. The Credit Card which is linked to your XBOX Live Account has Expired. Or some other problems with your Credit Card like your bank is not allowing you to use your Credit Card ( Make sure there is no problem with your Credit Card)
2. The country you are currently residing does not match with the region in your XBOX Live profile. If you have moved to a different country recently and trying to purchase from there ,you are most likely to get this error. (which Is the reason for my issue)
3. The Xbox live profile is temporarily blocked from purchasing in the Xbox Marketplace ( might be bcoz of more amount spent in a short time period / more unsuccessfull attempts when purchasing )
I suggest you to contact the XBOX Live customer Support in your region to get this sorted out. Check the below link for details.