I have attached the error screenshot for your reference. here it's window failed to apply.
1. First check whether those clients are online or not.
2. If not online, then ask your local IT and check.
3. If they are online, get one device on which its failing, connect through psexec or RDP or a remote tool and run gpupdate /force.. If a specific GPO fails to apply it will show you the ID.
4. With that ID check which GPO is failing to apply.
5. If its overall, no GPO is getting applied.. Then remove/delete the GroupPolicy folders under C:\Windows\System32 and then re-run gpupdate /force