Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Greetings!
This is Tin, I'm here to help you. Sorry to hear that you're unable to redeem your Product key to your account. The error that you're getting usually occurs when there's a pending balance on the previous subscription or the account has been locked due to billing issue. Kindly visit, https://account.microsoft.com/services, please make sure to clear the overdue subscription. Once done, please try to redeem again.
And in case it didn't help, you will be needing to reach the MS Accounts & Billing Support to check your account.
Kindly open this link: https://support.microsoft.com/contactus/
Ensure that your MS Account has been signed in (the one with the subscription)
Type "Chat with an agent" and hit Enter.
Please click the "Contact support"
Please select the "Products and services"
Please follow the prompts to connect with a live agent.
You may also choose the "Call me back" option if you prefer to receive a call.
Once you're connected to the Live Agent, please let them know about your issue so they could check your account and address your concern.
Thank you,
Christine L
Independent Advisor