Dear Manal Wael,
Good day!
Thank you for posting to the Microsoft Community. We are glad to assist.
Based on your post regarding with "can’t open my outlook account on the mobile app which pop up this message when I open it “ Mail has been blocked on this device by your administrator",it seem Outlook Account Blocked on Mobile Device by your system administrator.
please follow the below steps:
1. Contact Your IT Administrator: Reach out to your organization's IT support or helpdesk. They can provide details on why your device was quarantined and the steps needed to restore access. They may need to approve your device or make changes to your security settings.
2. Review Device Compliance Policies: Your organization might have specific compliance policies for accessing work emails on mobile devices. Make sure your device meets these requirements, such as having the latest updates or security configurations.
3. Office 365 Portal (Admin):
- As an admin, sign in to the Office 365 portal.
- Locate the affected user and open their settings.
- Under “Set sign-in status,” click “Blocked,” and then click “Save.” If needed, you can also set the status to “Allowed” and save it.
4. Confirm ActiveSync Status:
- In the Exchange admin center, check if the mobile device is blocked by an ActiveSync quarantine rule.
- Enable Exchange ActiveSync if it’s disabled, and try setting up the device again,
For more info: A mobile device can't connect to Exchange Online by using Exchange ActiveSync
Exchange ActiveSync device is blocked unexpectedly by ABQ list
Note: Please understand that our initial reply may not always immediately resolve the issue. However, with your help and more detailed information, we can work together to find a solution.
Thanks for your precious time. Have a nice day!
Microsoft Community Moderator