Why is Mac and iPad Continuity not working?

If you have a VPN App or profiles installed on your Mac or iPad, or a security/AV/firewall App such as Norton, these may be interfering with broadcast network traffic used by Apple's Continuity services. If applicable, you may only need to disable or remove the Security App and/or VPN.

You may also find that a restart of your WiFi Router, followed by a restart of your iPad and Mac will clear the problem….

To restart your router, disconnect power from the router for at least 30 seconds - then reconnect power to restart. After your router reboots (which may take several minutes), force restart your iPad:

Force restart iPad (models with Face ID or with Touch ID in the top button)

If your iPad doesn’t have the Home button, do the following:

1. Press and quickly release the volume button nearest to the top button.
2. Press and quickly release the volume button farthest from the top button.
3. Press and hold the top button.
4. When the Apple logo appears, release the top button.

Shut down or restart your Mac - Apple Support

What is not working on the issue, what Is the exact error that you're encountering