Trying to by 12 month xbox live gold with activation code

Thank you for your response. I have purchased a 12 month xbox live gold code and am trying to activate it but it is coming up with an error code of 5I288yfiG6R142PUs5IXEK.70 is there any chance you could help me with this as the live chat team were not very helpful.

You can buy 12 months of Live Gold at 3rd party stores in prepaid code and activate in your account.

12 months Live Gold gets converted into 4 months Ultimate Game Pass if you have a current, active Game Pass subscription.

To get the full 12 months of Gold you either need to wait till your UGP sub runs out then enter the code...or you need to cancel your GP sub and then enter the code

It is probably because you previously activated your game pass ultimate subscription. If you redeem a prepaid gold or game pass code while you have active the game pass ultimate subscription, the code will extend the time of the game pass ultimate subscription
but considering a conversion. A 12-month code of Xbox Live Gold extends a 4-month equivalent of a Game Pass Ultimate subscription.

Here is a link that contains information on equivalences.

https://www.xbox.com/live/gold/upgrade

then if you let you sub run out then you could have applied the 12 month gold card and got the full 12 months of xbox live gold, adding a gold card to a current active GPU sub will convert, done.