Unable to add funds to my child's XBOX account

Use this path first, since browser/app retries, cache clearing, and re-adding cards were already tried:

1. Sign in with the family organizer account at family.microsoft.com.
2. Open the child’s profile and select Add money or Manage spending > Add Money.
3. On the same Spending page, use a payment method listed under Child's payment methods. If needed, add it there with How to add a card.
4. If Manage spending appears, the child already has some balance. If Add money appears, the balance is currently zero.

Then check the payment blockers Microsoft documents for purchase failures:

1. On the Payment options page, confirm the card is current.
2. On the Services page, confirm there are no overdue subscription payments.
3. Confirm the organizer account is not temporarily suspended.
4. If the child uses Xbox, confirm the Xbox account is not suspended.
5. If using PayPal, it must have a credit card or confirmed bank account as its funding source.

Because the issue now fails in both the Family Safety app and web browsers, and the error explicitly says to contact support, the recommended next step is Microsoft Support. The documented support route is:

1. Go to Contact Microsoft Support.
2. Enter the problem and select Get Help.
3. If needed, select Contact Support to be routed to the best support option.

A practical workaround, if funds are needed immediately, is to add money by redeeming a Microsoft gift card on the Redeem page. For a child account, Microsoft also points to the family add-money flow instead of direct transfer. Keep in mind Microsoft account balance limits apply: up to USD 1,000 equivalent can be added or spent per day, and the maximum stored balance is USD 1,000 equivalent, with some country-specific exceptions.

Since travel was mentioned, country or region restrictions can also temporarily prevent redeeming money or making purchases when local limits are exceeded.

References:

• Add money to your family member's Microsoft account
• Troubleshoot buying issues with Microsoft Store
• Troubleshoot payment option issues
• Add money to your Microsoft account
• Limits on the money in your Microsoft account
• Cannot add funds to child account - suggested troubleshooting doesn't make a difference - Microsoft Q&A