Out of Range situations can be caused by such things as too much distance between the Parent Unit and Nursery Unit, Thick Walls between the Parent Unit and Nursery Unit or even a number of dividing walls in between the Parent and Nursery Unit.
The signal can also be weaker at times and this can also cause the Out of Range Indicator to come on. Unfortunately the strength of the signal is not something that you can change.
The AC1100 works on a Digital Frequency and not a Wireless Frequency, so there is a chance as with all wireless devices, they can be subject to some interference at times and this is not something that you may be able to change. Unfortunately as the AC1100 works on a Digital Frequency, it is not possible to extend the range on the AC1100.
This does not mean that your monitor is faulty.
Can we ask, how long have you been using the monitor and how long this has been happening.
Have you tried using it in a friend or relatives home to see if the interference is the same or better?
To improve your monitors performance please try the following:
Always keep your monitor away from other wireless devices.
Never operate your monitor in close proximity to a microwave, cordless or mobile phone.
Reorient or relocate your monitor to optimize reception, place away from WIFI or Router.
Never place a GSM cell phone or other Radio Frequency emissions device in close proximity or in contact with your monitor.
Reduce the distance between the Parent Unit & Nursery Unit.