Unable to update Xbox 360 or log into live account!

i dont know how to log on to xbox live on the 360... i did the connection test and it worked it updated whatever but it wont long on to xbox live with this account ...

The error message is : We were unable to sign you in with your Xbox Live account. Please visit xbox.com and sign in to verify/update your Xbox Live account. This error usually indicates that your microsoft account has no Xbox Live gamertag, or that your
account must be updated in some way, such as agreeing to an updated terms of use.

I think the account is a child account so how would I enable permissions? Tried after logging onto both websites and still get the error.

Using the 360 to access the website, I'm unable to log into my account

For about a year I have not been able to log into my account on any of my many 360s...I can log into Xbox One fine, but even when trying to play a 360 game on xbox one, it says that I am unable to log into xbox live on this console...it says try downloading
your gamertag again. I have in fact and last year changed my password like 5 times and still the same problem. There are a few 360 games on my xbox one such as gears 2 or 3 that I would like to play horde with, but I can't log into live on the 360 side to
do this, but I'm on live on the xbox one side.

I would be very grateful for some effective help.

regards,

SeaDrive

Everything matches email wise. When we try and log into fortnite it says unable to sign into your account for xbox live