Unable to sign-in to Microsoft Defender on Android devices for child accounts

Hello lespaulio, my name is Emmanuel.

I am so sorry to hear that you are having an issue signing in to your child's account with Microsoft Defender for Android. Kindly uninstall the Microsoft Defender app from the device of your child then go to this link https://aka.ms/AndroidDefender and install it from there then log in with your child's account.

Please also make sure that your child's email address you are trying to log in to is purely associated with the Microsoft Family account. Please check the spelling carefully.

On your child's Android device, please also go to the main SETTINGS > ACCOUNTS AND BACK UP > MANAGE ACCOUNTS > scroll down from the list of accounts that are currently logged in to your child's Android device and look for the Microsoft account and please make sure no Microsoft account is associated with work or school account. If there is, try signing out first from your work or school account on your child's device then log in to Microsoft Defender using your child's Microsoft Family account.

Hope this information can help you.

Let me know if this works for you.

Emmanuel,

Thanks for your reply. I tried reinstalling using the method you suggested and it did not help, I still get the same error. My child's email address was just created and is purely associated with the Microsoft Family account. It is being spelled correctly. Again, I am not getting an error related to invalid username or password, but that the "license" associated with the accounts are invalid.

As I mentioned, these Microsoft accounts were just created for this purpose and are not associated with any work or school account. This same issue is happening with two separate accounts on two separate Android devices. Any further assistance you can offer would be appreciated. Thanks.

Are your child's email addresses both an Outlook email?

Yes, both are @outlook.com email addresses.

Can you try logging in using your own Microsoft account on their devices to see if you can log in successfully?

Actually, even if you don't have an existing Microsoft 365 Personal or Family subscription, you should still be able to log in successfully using an Outlook email address without any error. It's just that once you logged in, you will be seeing a prompt message asking to get a Microsoft 365 subscription either PERSONAL or FAMILY to be able to use Microsoft Defender.

Here is the actual screenshot of the prompt message when logged in to the Microsoft Defender app for Android using an Outlook email without a Microsoft 365 subscription.