Having an issue with signing in…

So we’ve tried all that with his phone. No text messages from Xbox coming through still. He can receive messages from anyone else

Hello Gingerbread,my name is Marvina, I will be happy to help you.

Here are some suggestions to fix the problem of your brother not receiving the login verification code on his mobile:

Check your mobile settings. Make sure your phone is set up to receive text messages from Microsoft.

To do this, open your mobile settings and look for the "Messages" section.

Next, look for the “Allow text messages from Microsoft” option and make sure it is turned on.

Check your Microsoft account settings.

Make sure your Microsoft account is set up to receive verification text messages.

To do this, go to your Microsoft account security page and check the "Two-Step Verification" section.

Next, make sure “Send a text message” is turned on.

Try a different phone number. If you have access to another phone number, try using that number to receive the verification code.

Try signing in to your Microsoft account in a web browser.

If you can sign in to your Microsoft account in a web browser, you can generate an 8-digit verification code that you can use to sign in to your Xbox console.

To do this, go to your Microsoft account sign-in page and click the "I can't access my account" link.

Next, select the "I'm not receiving the text message" option.

Regarding your brother's suggestion to create a new profile, it is true that she will lose the games she purchased on that account if she creates a new profile. However, there are some games that can be transferred from one account to another.

Source: https://support.xbox.com/help/account-profile/signin-security/did-not-receive-security-code

These are basic solutions to these problems, but they can lead to a solution, remember that this is a public forum where we are players like you who want to help, good luck and happy day.

Sincerely,
Marvina.

Hiya,

For any sort of beta related issues, please make sure to post in the beta dashboard forums
here.

If you don't have access to that section of the forums just yet and you're seeing "GROUP NOT FOUND" then please be patient as a forum support agent will need to look into your participation in the beta,
once they have confirmed that they will add you to that section of the forums.

Please Note: You can only gain access to the beta forums if you have the "beta" channel on your Xbox 360 Dashboard. Only the person who ran the beta registration application will have access to the forums using their gamertag. No other gamertags
will be able to access the forums. Since beta registration is now closed, it's not possible to get another console into the beta so you'd need to wait until the beta is released to the public later this year to make any purchases, or visit anyone's
house you know of that also has this beta update to make purchases on their console for the time being.

Hi, I am Mariano, an independent advisor from the Microsoft-Xbox community. I am sorry you are going through this issue, let us try to fix it

Please note that this is a public community forum, so we're players like you, not Microsoft employees. Therefore, we don't have access to any user accounts. We're trying to help you resolve this issue.

You're not the only one experiencing this issue—other players are having similar problems with their Minecraft accounts.

I recommend contacting Minecraft Support by submitting a ticket here:

https://help.minecraft.net/hc/en-us/request/new

Be sure to mention that you're facing the same issue as many others.

The support team is trained to help with this kind of account problem and should be able to assist you.

Your account is still there in the cloud, so don't worry about being able to redownload it.

It very likely is still a leftover problem from yesterday. If the problem persists, and power cycling as XBF said doesn't help contact Xbox Support

I suggested deleting and redownloading your account, because it along with power cycling are the least hassle to do, compared to factory resetting.

I know how aggravating it can be when Xbox Live doesn't work right.

I would give it a couple of hours and then try signing in again

Hopefully it works for you sooner then later.