Hi Hannah,
It appears that the device does not meet your Conditional Access Policy requirements. To address this, review the configuration of your Conditional Access Policy.
For detailed information about the failure and the affected Conditional Access Policy in the sign-in logs, refer to the troubleshooting steps outlined in the following link:
Conditional Access Troubleshooting Guide
This guide will help you identify the specific reasons for the failure and guide you through the necessary adjustments to meet your Conditional Access Policy requirements.
If you are able to login to your Entra ID (AAD) you will be able to check the audit/sign-in logs on your account to see the exact reason for the error code.
If this is helpful please accept answer.