If there is an object obstructing or interfering with the wireless signal between the TV and the mobile device, the picture quality may be unstable or blurry when using one-touch mirroring or screen mirroring. To avoid this, remove any objects blocking the wireless signal between the mobile device and the TV. Placing the mobile device near the TV can also fix the issue.
In addition, the Xperia mobile device has a built-in Wi-Fi® antenna. Covering this built-in Wi-Fi antenna may not achieve the one-touch mirroring feature or the screen mirroring on your TV. Make sure that this built-in Wi-Fi is not being covered by your hand to avoid unstable picture quality. Refer to the instruction manual of your Xperia mobile device for the location of the built-in Wi-Fi antenna.