wsus clients not installing CU or Security updates

Question

My wsus server (Server 2019) has all CU and security updates approved and says they are downloaded, but my clients (which are running on Windows 10 1909) aren't seeing them as available. When they check for updates, they just say that they're up to date.
Wsus server sees the clients, but says previous updates (from a few months ago) are the only ones needed.
Any idea what could be wrong?

Answer 1

1909 is end of life (For home and pro)

https://learn.microsoft.com/en-us/lifecycle/announcements/windows-10-1909-end-of-servicing

Upgrade to a supported version to allow WSUS to patch your client systems.

https://www.ajtek.ca/wsus/how-to-setup-manage-and-maintain-wsus-part-3-windows-as-a-service-waas-and-group-policy-administrative-templates/