Note: Here's a list of Pre-Requisits you can check to avoid troubleshooting issues.

Web-AuthN requires devices with a TPM chip or Secure Enclave and screenlock enabled	Web-AuthN supports the following browsers	AuthN app	Access Requirements	Registration
Windows PCs	Microsoft Edge	Android 6.0 or higher with permission for app overlay	Global Admin	User certificate with user email for device registration
Macs**	Chrome	iOS 11 or higher
iPhones, iPads handhelds**	Safari	iPadOS 13 or higher
Android handhelds	Internet Explorer 7 or higher
Chromebooks
Thin-clients
**Apple requires the use of iCloud Keychain for the use of Web-AuthN

Proof of Concept Deployment Guide (M365 Only)