Hi @John Hogan,
Thank you for posting your question in the Microsoft Q&A forum.
Based on your sharing, the issue is highly due to a licensing issue. Since you have admin access, you can check your licenses and user assignments in the Microsoft 365 admin center by following these steps:
1- Check your Teams license
- Go to the Microsoft 365 admin center with your admin credentials.
- In the left-hand navigation pane, expand the Billing section and click on Your products.
- This page lists all the subscriptions you own. Look for your Microsoft 365 Business subscription (e.g., "Microsoft 365 Business Standard") and see if you see a subscription with a "(no Teams)" tag
2- Check individual user licenses:
- In the Microsoft 365 admin center, go to Users > Active users.
- Select the user account you're trying to set up Teams for.
- In the user's profile pane, click on the Licenses and apps tab.
- Expand the list of apps for your subscription and look for "Microsoft Teams." Make sure the checkbox next to it is selected. If it isn't, check it and save the changes.

3- Check if Sign-in is enabled in the Azure Active Directory
- Log into Microsoft 365 global admin and navigate to Azure Active Directory Admin Center.
- Select Enterprise applications in the left pane and select Manage > All applications.
- Set the Application type filter to Microsoft Applications and Applications status to Disabled, then click Apply to save changes.
- Now, select Properties under Manage and set the “Enabled for users to sign-in?” option to Yes.
- Lastly, click on Save to save the changes.
- Try logging in again and see if the error AADSTS7000112 Application is disabled still appears.

Note: Please understand that our initial response does not always resolve the issue immediately. However, with your help and more detailed information, we can work together to find a solution.
I hope this information is helpful. Please follow these steps and let me know if it works for you. If not, we can work together to resolve this.
Thank you for your patience and your understanding. If you have any questions, please feel free to reach out.
I'm looking forward for your reply.
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