Redeem A 14 day xbox live trial but it won't let me use it

To clear it up. If you have an existing 30 days subscription(trial or not). You should not be able to redeem a 14 day trial. If you where able to redeem a trial code during this period, then that 14 day trial will be useless as it won't stack with your 1
month subscription. Once your 1 month subscription ends, everything ends. It won't continue your trial subscription that you redeemed within those period.

So basically, if you have a free 2, 7 or 14 days trial. It is best to be used after an existing subscription ends. And make sure not to redeem them all at once. If you have redeemed a 14 days trial first then redeemed another 2 days trial, it won't stack.
It will overwrite the first one you redeemed. So instead of getting 16 days, you will only get 2 days of trial subscription.

I hope that clear things up regarding trial subscriptions.

Were you using a 14 day trial before you redeemed this code ?

What if I'm on a 14-day prepaid code trial and I upgrade to Xbox Live Gold during the trial period to take advantage of a free game offer? Will I get the game?

If you upgrade to Xbox Live Gold during your non-renewing trial period, your Xbox Live Gold membership won't start until the end of your free trial.
You won't be eligible to download a currently offered free game until your trial period ends and your paid membership begins.

Please bear in mind Xbox Gold trials does not stack to each other. If you redeemed a 14 day trial code then redeem a 2 day code it will remove the 14 day trial code. Have you redeemed other codes besides the 14 day trial?

Dear Support,

Thank you for the fast reply!

Er...my question is that a 'xbox game pass ultimate 14 days trial codes' could be used/sold as 'xbox game pass 14 days trial code' or 'xbox gold live 14 days trial code', right?

I understand that a xbox game pass 14 days trial code or a xbox live gold 14 days trial code can't be used/sold as xbox game pass ultimate 14 days trial code for sure.

Because a 'xbox games pass ultimate 14 days trial code' equals a 'xbox game pass 14 days trial code + xbox live gold 14 days trial code', so for new Microsoft/Xbox accounts, a 'xbox game pass ultimate 14 days trial codes' could be used/sold as 'xbox game
pass 14 days trial code' or 'xbox gold live 14 days trial code' , right?

Please help to clarify.

Thanks again for your time!

I have already changed the Ethernet cable and reconfigured the ICS several times, it won't let me connect to Xbox Live. I remember I redeemed a code in which I could use the Xbox Live Gold Membership for 14 days in the same day this error started happening.