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Hello @Gareth Strachan,
Thank you for reaching out to the Q&A forum!
Could you please confirm if the error code you mentioned (99287) is correct, or if it might actually be 399287?
If it is 399287, this error during the two-factor authentication (2FA) process typically indicates that the phone number associated with your account has been flagged by Microsoft’s internal system (Phone Reputation), which prevents SMS or call verification from being sent.
To support you better, please clarify the following:
- Based on your email address, it appears to be a work account. Are you an administrator or a regular user in your organization?
- If you are an administrator, is there another admin who can access the Microsoft 365 Admin Center?
Each scenario will have different instructions, so to help you in the right direction, please provide me with this information.
Please understand that our initial response may not always resolve the issue immediately. However, with your help and more detailed information, we can work together to identify the root cause and find a solution.
Looking forward to hearing from you.
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