There can be many causes for lag and dropping connection on Xbox One. Below are several things you can check to improve this:

  1. Make sure that your Wi-Fi router is running the latest firmware. In some cases, this can also improve screen mirroring performance and reduce lag.
  2. If your Wi-Fi router supports Wi-Fi isolation or network isolation, as is common on guest networks, make sure that these settings are turned off. This will fix any discovery issues that you may be experiencing with AirPlay or Google Cast.
  3. Make sure to restart your Xbox, router and the device you want to initiate screen mirroring from at least once.
  4. Use iStumbler (Mac) or NetStumbler (PC) to see which WiFi channels are in use around you, then configure your router to use a channel which is free. You should preferably also configure your router to only use WiFi-n or WiFi-ac (if supported).
  5. Make sure you are using the latest version of AirServer for Xbox One by checking for updates.
  6. Connect your Xbox to your network using an ethernet cable. This will greatly improve reliability, reduce audio stutters and lag.
  7. If you have no way of hardwiring your Xbox One into the network, make sure you are in sufficient range for the wireless network.
  8. Make sure to switch power off and on to avoid any memory issues on your Xbox One.