Several controllers in one area

[peacemakerv]

HI, All

I'm making testing 5 controllers at the same time in one room. Developing my own FW for ESP32, as before did and worked OK.
But i have found that if several my KC868-A6 boards (2...5pcs) are online (via single WiFi-router) - there are many transmission errors.
If to switch all off excepting one - no any errors at all ! Fully OK working with a server.

It is strange, i'm sure. 
Is it known subject ? Any ideas why?
I need to use 3-4 pcs in some area of maybe 10 meter radius.

[admin]

i think it's problem with your router. you can replace router, or change the wifi channel of your router.

[peacemakerv]

i think it's problem with your router. you can replace router, or change the wifi channel of your router.

YES! Thanks. Changing channel number from 3 to 12 helped a lot.

[admin]

ok, good.