<t>As per Microsoft data retention policy, if a tenant remains inactive without any sign-in activity, the account gets disabled, and customer data deleted.<br/>
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If you don't log in to your Azure tenant via https://portal.azure.com/ within the specified time frame, it may be permanently deleted. Inactivity can trigger Microsoft's process to remove unused tenants. Once a tenant is marked as inactive, the OMS commerce system enforces a login block. During this time, any sign-in attempts will result in the following error: "AADSTS5000225: This tenant has been blocked due to inactivity."<br/>
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Twenty days after the login block is applied, the tenant will be permanently deleted.<br/>
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Since you mentioned you are not aware of your old tenant and not used for production, you should re-create a new tenant for your purposes.<br/>
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Solution : To fully utilize the Azure portal, you need to re-create your new tenant.<br/>
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Follow these steps:<br/>
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- Open an in-private/incognito browser window (to avoid automatic sign-in via SSO).<br/>
- Navigate to https://azure.microsoft.com/en-us/free/ to sign up for a free Azure account.<br/>
- During the setup, you'll be prompted to create a new directory (tenant). Once completed, you will become the Global Administrator of this new tenant, giving you full access to manage Azure resources.<br/>
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For more details about inaccessible tenants, refer to: Tenant inaccessible due to inactivity</t>