Hi Daniel Simpson,
Welcome to Microsoft Q&A forum and apologize for the inconveniences that you are facing right now.
Please feel free to try these steps to see if they help:
- When changing your password, make sure the optional “Make me change my password every 72 days” box is unchecked. For your reference: Change your Microsoft account password
- Kindly re-check again and remove any unknown connected apps/services that still have access to your account (these can sometimes keep triggering security prompts).
- If it still continues after that, the best next step is to visit Microsoft Support - Contact Us to have an agent have a further look into this matter for you
Please note that this is a user-to-user support forum. Moderators and contributors, including external Microsoft employees, are not allowed to directly interfere with Microsoft product features or access back-end systems. Our role is limited solely to providing technical guidance on reported incidents, requests, or ideas.
Thank you for your understanding.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.