The ADSL modem/router/WiFi AP Edimax AR-7286WNB allows only up to 8 connected devices at a time. That includes phones on standby.
As I only use this modem rarely, it took me some time (years) to realize this limit. There never was any error in long in web admin.
What angers me is that the manufacturer doesn’t list this limit anywhere on product site, specification sheet or manual. WiFi AP allows to setup 4 SSIDs but the limit is shared among all of them.
That’s graphics from products site. It gives impression that it can handle lot’s of devices while it’s not sufficient for single family – and I’m not even using WiFi light bulbs, just phones, tablets, laptops and TVs.