The cause of this is most likely due to wireless interference
(often prominent in apartment buildings and complexes) or simply that the wireless signal is not reaching the distance from your router to your device.
One option is to invest in a higher spec dual-band or tri-band router, so that you can get a larger frequency range to work with when changing channels on your router.
A standard router single band router transmits on the 2.4GHz band, where as a dual-band router transmits two simultaneous signals; one on the 2.4GHz band and one on the 5GHz band.
Another option would be getting your IT company to install cabled wireless access points throughout your property to ensure wireless reaches all corners
of your home or business.
However, do keep in mind that regardless of the solution you choose, wireless is susceptible to interference and we would like should remind you that it is always better to be "cabled in" for as many fixed devices as possible.