Hello @Akeem Ojo-Oniyun,
Thank you for posting your query on Microsoft Q&A.
Based on your description, it seems you're encountering an error message that says "Security key challenge has expired" when attempting to add a FIDO key. I've attached a screenshot for reference.
I would like to inform you that this issue was reported by several customers on September 3rd. Our Product Group (PG) team has identified and resolved the problem. Please check again and confirm if you are now able to successfully add the FIDO security key.
I hope this information is helpful. Please feel free to reach out if you have any further questions.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Thanks,
Raja Pothuraju.