RT-AC86U and ESP8266 DHCP problem?

[Herrero]

I have upgraded AC-RT68U to AC-RT86U and I have a problem with my temperature and humidity sensors (based on ESP8266). I have read a lot of topics about problem with ESP8266, but I think my is different. My nodes are reading temperature and humidity once per 5 minutes and are sending to my server in my LAN. After sending measurements the are going to sleep for 5 minutes (so, they are going to disconnect from WLAN). Some times they working couple of hours, sometimes couple of minutes. I think they have problem with obtain IP adress from DHCP. Below I present log when they dont work:

Mar 18 16:47:20 dnsmasq-dhcp[1937]: DHCPDISCOVER(br0) a4:cf:12:f5:28:6a
Mar 18 16:47:20 dnsmasq-dhcp[1937]: DHCPOFFER(br0) 10.10.10.14 a4:cf:12:f5:28:6a
Mar 18 16:47:30 dnsmasq-dhcp[1937]: DHCPDISCOVER(br0) a4:cf:12:f5:28:6a
Mar 18 16:47:30 dnsmasq-dhcp[1937]: DHCPOFFER(br0) 10.10.10.14 a4:cf:12:f5:28:6a
Mar 18 16:47:54 dnsmasq-dhcp[1937]: DHCPDISCOVER(br0) a4:cf:12:f5:28:6a
Mar 18 16:47:54 dnsmasq-dhcp[1937]: DHCPOFFER(br0) 10.10.10.14 a4:cf:12:f5:28:6a
Mar 18 16:48:16 wlceventd: wlceventd_proc_event(507): eth5: Disassoc A4:CF:12:F5:28:6A, status: 0, reason: Disassociated because sending station is leaving (or has left) BSS (8), rssi:0
Mar 18 16:48:16 wlceventd: wlceventd_proc_event(490): eth5: Deauth_ind A4:CF:12:F5:28:6A, status: 0, reason: Class 2 frame received from nonauthenticated station (6), rssi:0
Mar 18 16:48:16 wlceventd: wlceventd_proc_event(490): eth5: Deauth_ind A4:CF:12:F5:28:6A, status: 0, reason: Class 2 frame received from nonauthenticated station (6), rssi:0
Mar 18 16:48:16 wlceventd: wlceventd_proc_event(490): eth5: Deauth_ind A4:CF:12:F5:28:6A, status: 0, reason: Class 2 frame received from nonauthenticated station (6), rssi:0
Mar 18 16:48:16 wlceventd: wlceventd_proc_event(490): eth5: Deauth_ind A4:CF:12:F5:28:6A, status: 0, reason: Class 2 frame received from nonauthenticated station (6), rssi:0
Mar 18 16:48:16 wlceventd: wlceventd_proc_event(490): eth5: Deauth_ind A4:CF:12:F5:28:6A, status: 0, reason: Class 2 frame received from nonauthenticated station (6), rssi:0
Mar 18 16:48:16 wlceventd: wlceventd_proc_event(490): eth5: Deauth_ind A4:CF:12:F5:28:6A, status: 0, reason: Class 2 frame received from nonauthenticated station (6), rssi:0
Mar 18 16:48:16 wlceventd: wlceventd_proc_event(490): eth5: Deauth_ind A4:CF:12:F5:28:6A, status: 0, reason: Class 2 frame received from nonauthenticated station (6), rssi:0
Mar 18 16:48:16 wlceventd: wlceventd_proc_event(490): eth5: Deauth_ind A4:CF:12:F5:28:6A, status: 0, reason: Class 2 frame received from nonauthenticated station (6), rssi:0

and when they work:

Mar 18 17:58:37 dnsmasq-dhcp[20736]: DHCPDISCOVER(br0) a4:cf:12:f5:28:6a
Mar 18 17:58:37 dnsmasq-dhcp[20736]: DHCPOFFER(br0) 10.10.10.14 a4:cf:12:f5:28:6a
Mar 18 17:58:37 dnsmasq-dhcp[20736]: DHCPREQUEST(br0) 10.10.10.14 a4:cf:12:f5:28:6a
Mar 18 17:58:37 dnsmasq-dhcp[20736]: DHCPACK(br0) 10.10.10.14 a4:cf:12:f5:28:6a ESP-F5286A
Mar 18 17:58:38 wlceventd: wlceventd_proc_event(507): eth5: Disassoc A4:CF:12:F5:28:6A, status: 0, reason: Disassociated because sending station is leaving (or has left) BSS (8), rssi:0
Mar 18 17:58:38 wlceventd: wlceventd_proc_event(490): eth5: Deauth_ind A4:CF:12:F5:28:6A, status: 0, reason: Class 2 frame received from nonauthenticated station (6), rssi:0
Mar 18 17:58:38 wlceventd: wlceventd_proc_event(490): eth5: Deauth_ind A4:CF:12:F5:28:6A, status: 0, reason: Class 2 frame received from nonauthenticated station (6), rssi:0
Mar 18 17:58:38 wlceventd: wlceventd_proc_event(490): eth5: Deauth_ind A4:CF:12:F5:28:6A, status: 0, reason: Class 2 frame received from nonauthenticated station (6), rssi:0
Mar 18 17:58:38 wlceventd: wlceventd_proc_event(490): eth5: Deauth_ind A4:CF:12:F5:28:6A, status: 0, reason: Class 2 frame received from nonauthenticated station (6), rssi:0
Mar 18 17:58:38 wlceventd: wlceventd_proc_event(490): eth5: Deauth_ind A4:CF:12:F5:28:6A, status: 0, reason: Class 2 frame received from nonauthenticated station (6), rssi:0
Mar 18 17:58:38 wlceventd: wlceventd_proc_event(490): eth5: Deauth_ind A4:CF:12:F5:28:6A, status: 0, reason: Class 2 frame received from nonauthenticated station (6), rssi:0
Mar 18 17:58:38 wlceventd: wlceventd_proc_event(490): eth5: Deauth_ind A4:CF:12:F5:28:6A, status: 0, reason: Class 2 frame received from nonauthenticated station (6), rssi:0
Mar 18 17:58:38 wlceventd: wlceventd_proc_event(490): eth5: Deauth_ind A4:CF:12:F5:28:6A, status: 0, reason: Class 2 frame received from nonauthenticated station (6), rssi:0
Mar 18 17:58:38 wlceventd: wlceventd_proc_event(490): eth5: Deauth_ind A4:CF:12:F5:28:6A, status: 0, reason: Class 2 frame received from nonauthenticated station (6), rssi:0

To fix the problem I have to do one of these things:
- turn off/on 2.4GHz radio,
- connect to 2.4GHz network form my laptop (very weird),
- restart router.
I have disabled beamforming, MU-MIMO and etc. (I have read about Tasmota and ESP8266 problems). I attached my configuration of 2.4GHz WLAN. The same problem persist on the last stable Merlin (386.1_2 ) and Asus stock firmware.

I think, that the problem is not related with signal strength (RSSI of sensors is between -60 and -80dBm) and is not related with their firmware (they worked with no problem since september). In logs I didn’t find anything usefull…
Thank you for any help and suggestions.

 

[ColinTaylor]

This appear to be the same problem that has been widely reported in numerous threads in these forums. Namely, the router sends a DHCPOFFER but never receives a DHCPREQUEST from the client.

 

[sfx2000]

See if you can disable Airtime Fairness

 

[Herrero]

See if you can disable Airtime Fairness

Yes, it is disabled.

I did the small research. I was analizing wlan traffic via Kali Linux and I noticed that sometimes the ESP8266 deviced are trying to connect in very old 802.11b standard. If any of them was trying this kind of connection all of them were unable to connect to Asus. I don't know why new associaction from my notebook unblock Asus?

The solution (in my case) is change the 2.4GHz network mode to "legacy". Everythink works from 72h