In general, your Mac before 2011 and almost all Windows PC are not available for AirPlay mirroring, thus leading to the problems of iPad AirPlay mirroring not working on computer. So, it’s extremely urgent to get an AirPlay server to turn Mac or PC into an AirPlay-compatible device to display contents streamed from iPad. In addition to that, there are also some other factors causing iPad screen mirroring not working.
1. Make sure that your devices are on and nearby. If you try to AirPlay iPad audio to multiple speakers with AirPlay 2, make sure that the speakers are AirPlay 2 compatible.
2. Upgrade your iPadOS to the latest version.
3. Connect the devices to the same WiFi network.
4. Check the AirPlay settings to be the right situation.
5. If you need to screen mirroring iPad to computer, make sure you have got the Bonjour downloaded and installed on your computer. In case needed, you should also change the network firewall settings to allow the app on your computer to get through the firewall.