@Bytez Assuming they're flashing amber you may have hit the wifi client count for your router (depending on the router it's 20-50, not the 254 or so in the DHCP space).

  @Bytez Could be they have weaker wifi radios if they're a different version, or have trouble due to their location, or sometimes they may be connecting to the wrong AP if you have multiple.

You didn't mention though - what do you mean by "fall off the network"?  Are they flashing amber, showing "not available in the app", or did you check your router's wifi client status?

I'm curious how you know the number of wifi clients your router supports?  It's constrained by the chip set used by the router and is not the same as max clients.  Most router manufacturers don't publish this limit.  When the limit is hit the routers start dropping the last client to connect - with many devices it doesn't matter, they just reconnect on the next outgoing request.  Some home automation devices like switches are passive and wait for an incoming connection - they don't seem to detect they've been dropped for a while.

Hello  @Bytez 

HS200 only support 2.4Ghz wifi band.

You could connect a HS200 to Guest Wi-Fi network and see if the issue stops.

Confirm smart device received strong signal strength ; camera settings-> Wifi router tap wifi icon to check the dBm,-40~-60 are good, -60~-70 are acceptable, less than -70dBm, try to locate router closer to smart devices

to help isolate the issue, can you help provide some information here

• model of wifi router and network topology, e.g ISP XX-- router model XX<wireless>HS200 
• can I know the wifi Led status ON HS200 when issue happen , is it red or flashing green, if press 'Reboot' button, could HS200 recovers ?
• what is the firmware & hardware version of router? When issue happen, please check router log and see if there is any error related to HS200 V5
• Please share the Mac of the smart device with issue to us via private message, thank you