@Bruno Alves, Thanks for posting in Q&A.
To narrow down the issue, please check the following.
1.Check the device status: Make sure the problematic devices are showing as "Compliant" in Intune. If they are not, then they might have some compliance issues that need to be resolved before they can sync with Intune.
2.Check the device enrollment: Verify that the devices were enrolled correctly. Check if the devices are showing up in the Intune portal and the devices' policies are applied correctly.
3.Windows 10 settings: Check if there are any Windows 10 settings that might be causing issues with Intune. For example, check the device settings for Windows Update, and make sure they are not configured to block updates.
4.Logs: Check the logs on the problematic devices for any errors or warnings related to Intune. Location: Event Viewer > Applications and Services logs > Microsoft > Windows >DeviceManagement-Enterprise-Diagnostics-Provider > Admin
5.Try a manual sync: You can try initiating a manual sync from the problematic devices. This can be done by going to Settings > Accounts > Access work or school > Select the account > Info > Sync.
6.Please be sure Intune MDM device cert is still valid and no licensing issues.
https://call4cloud.nl/2021/04/alice-and-the-device-certificate/
Non-official, just for reference.
7.Check Firewall Port 444 of the System and Enterprise Mobility + Security status, and if the device registered to multiple organizations.
https://www.thewindowsclub.com/windows-10-devices-cant-sync-with-intune-after-enrollment
Non-official, just for reference.
If there is any unclear, feel free to let me know.
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