Whilst, at times your Baby Monitor could interfere with your WIFI signal, it cannot totally block it.
It is not possible to change the channel on your monitor operates on. It auto selects the optimum channel available when in actual use.
Interference can be caused by such things as:
Too much distance between the Parent Unit and Nursery/Camera Unit, thick walls between the Parent Unit and Nursery/Camera Unit or even a number of dividing walls in between the Parent and Nursery/Camera Unit.
Stone, and water (large fish tank)
Ceramic, concrete, metal, and mirrors, these reflect visible light and radio waves
"Outside energy”, such as another, stronger signal outside of your home and also inside it
The signal can also be weaker at times and this can also cause interference. However, the signal strength of the monitor is not something that you can boost.
Unfortunately, the 2.4GHz frequency your monitor operates on is becoming “busier” as more and more wireless products are populating this frequency, people liken it to a 3-lane motorway usually at peak time, it gets congested.
We do know that some users change the frequency that the router is operating on to bypass any interference as these also generally operate on the 2.4GHz frequency that your monitor is operating on
OR, reposition the router - please check with your supplier for advice