TP-Link TL-WR841N openWRT 15.05.1 can only connect up to 2 wireless devices to internet by wifi

[john36421]

first 2 devices (android) connect ok to my home wifi router and get internet access
third device (android) trying to connect to wifi router is stuck on "obtaining ip address" when network in android defined as dhcp
if setting static ip (+ dns) for example by wifi settings app
device DOES connect to lan, but still cannot connect to internet
here is print screen of openWRT (third problematic device which won't connect is marked with yellow with TX Rate 1.0 Mbit/s MCS 0 which always shown for device that cannot connect)


the point is that third device is random and not always specific one.
actually sometimes all devices fail to connect to internet until i restart router, change device connection type from dhcp to static ip or back

-router is connected to my pc with cable and pc always has internet access
-cable connected from cable modem to WAN port (blue) on router and cable between router and pc is from one of 4 yellow lan ports on router.
-router doesn't feel hot when i touch it
-if i set wireless hotspot on my phone - the third problematic device successfully connects to it and gets internet access

things that i found on web but didn't help:
-i tried moving to another channel (11,13,1)
-i tried removing wifi security temporarily
-tried lowering Transmit Power
-tried setting Operating frequency to legacy mode (below n)

can anyone help to fix that or at least to understand the reason?

 

[Ralston18]

On your router look for a setting that involves the range of available DHCP IP addresses.

When using DHCP the router can be configured to use a specific number of IP addresses or range.

May appear as a start IP and End IP address box.

Example: Start IP could be 192.168.1.2 and End IP could be 192.168.1.4. That allows 3 devices to connect via DHCP. (With the router itself being 192.168.1.1 which is one of the normal home router addresses.

And if you happen to assign some device a static IP address in that range you will have problems via duplicate IPs.

Make sure all devices are DHCP with the correct subnet mask.

 

[john36421]

thanks for reply

before a hour i fixed it myself, by reverting back to original firmware from tp link.
with help of following great guide from openWRT forum:
Simple fast way to revert to stock firmware

now all devices connect to internet with default dhcp connection type and default router settings