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I have just replaced my old Wireless Access Point which only supported 2.4GHz with a dual-band one (TP-Link Archer C6) which also features TxBF, MU-MIMO (Transmit Beamforming, Multi-User Multiple-Input Multiple-Output). Previously, I had no problem connecting to the Wifi. However, my 19.10 laptop will now only connect to the 5GHz network - the 2.4GHz network is detected but will not connect with TxBF, MU-MIMO enabled.

I have another laptop running 18.04 LTS, which can switch between both networks without issue. The 19.10 laptop has an Atheros AR9462 card, while the 18.04 laptop has an Intel 8265NGW card. I have tried swapping the cards, and the 19.10 laptop still won't connect. I have tried booting both laptops with live 19.10 and 18.04 systems from USB. In both cases, 19.10 will only connect to the 5GHz network, while 18.04 will connect to either.

I also have a Realtek RTL8188CUS USB 2.4GHz dongle, this will connect to the 2.4GHz network on 19.10.

I can disable TxBF, MU-MIMO in the access point's settings and use it fine, however I would like to understand why this doesn't work on 19.10.

Wireless card details:

  *-network                 
       description: Wireless interface
       product: AR9462 Wireless Network Adapter
       vendor: Qualcomm Atheros
       physical id: 0
       bus info: pci@0000:01:00.0
       logical name: wlp1s0
       version: 01
       serial: 30:10:b3:37:a8:9b
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list rom ethernet physical wireless
       configuration: broadcast=yes driver=ath9k driverversion=5.3.0-24-generic firmware=N/A ip=192.168.0.64 latency=0 link=yes multicast=yes wireless=IEEE 802.11
       resources: irq:16 memory:d1000000-d107ffff memory:d1080000-d108ffff

dmesg output when connecting to 2.4GHz:

[ 2647.107528] wlp1s0: authenticate with 74:da:88:e1:74:9e
[ 2647.120808] wlp1s0: send auth to 74:da:88:e1:74:9e (try 1/3)
[ 2647.125483] wlp1s0: authenticated
[ 2647.130299] wlp1s0: associate with 74:da:88:e1:74:9e (try 1/3)
[ 2647.232374] wlp1s0: associate with 74:da:88:e1:74:9e (try 2/3)
[ 2647.340427] wlp1s0: associate with 74:da:88:e1:74:9e (try 3/3)
[ 2647.444415] wlp1s0: association with 74:da:88:e1:74:9e timed out
Gabriel Staples
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mark johnson
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  • Bring up the NetworkManager GUI for wireless networks. Find the one for the 2.4ghz network that you can't connect to. "Forget" that connection. Now retry connecting. Report back. Start comments to me with @heynnema or I may miss them. – heynnema Dec 16 '19 at 01:09
  • @heynnema Yep I have tried removing and re-creating both networks, it doesn't resolve the issue. 5GHz always works first time on a live 19.10 system, but 2.4GHz not at all. – mark johnson Dec 16 '19 at 09:45
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    What channel is the 2.4ghz wireless set to? If it's set to auto, and it's a Euro router, it might be trying channels 12-14, which isn't valid in the US, or with most modem cards. Try setting it to 6 and see if there's any difference. Check your 2.4ghz settings in the router. Look for settings like "beacon", or other timing related settings. I might be in the "Advanced" menus. – heynnema Dec 16 '19 at 14:36
  • @heynnema It's set to auto, but currently using channel 5. I am in the UK. This does not change when I am successfully connecting with 18.04 on the same hardware. There is no Beacon setting. – mark johnson Dec 16 '19 at 16:38
  • I would try the old access point, and see if 2.4ghz still works there. If it does, I'd do a factory reset on the Archer C6 and retry 2.4ghz. Was that a new router, or a used/refurb? If you'd like to screenshot your wireless, and advanced wireless setup pages, I'll take a look for you. – heynnema Dec 16 '19 at 17:19
  • @heynnema I looked at the settings again and tried disabling TxBF, MU-MIMO (Transmit Beamforming, Multi-User Multiple-Input Multiple-Output) then rebooting the access point. I can now connect to the 2.4GHz network. I will update the question to reflect this. Thanks for helping me track this down. – mark johnson Dec 17 '19 at 17:40
  • Well, now I've re-enabled MU-MIMO and rebooted the access point again, and everything works. Not very helpful, but I guess it was just a random glitch. – mark johnson Dec 17 '19 at 18:13
  • TxBF and MU-MIMO should both be enabled. Reboots sometimes fixes things. – heynnema Dec 17 '19 at 18:34

4 Answers4

4

In my case disabling and enabling TxBF, MU-MIMO didn't change much. However, switching from wpa_supplicant to iwd fixed the problem.

This approach was originally proposed here: https://forums.linuxmint.com/viewtopic.php?p=1835081&sid=96653a1f3594e9c8aa1ea7934ba09a7c#p1835081

Jacajack
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    Do confirm the same problem with TP-Link Archer C6 (ver 2.0 EU) with an Intel AC 3165 wifi card on a dell laptop. 2.4 GHz of other APs were connecting, but only on tplink it was timing out or something. Even WPS didnt work. Tx-bf, mu-mimon & changing all sys parameters on the router didnt work.

    It works in Windows though, as is. In Ubuntu, 5GHz always connects. SOLUTION: switching from wpa_supplicant to iwd fixed the problem. IT DID, really.

     – naks Aug 19 '20 at 16:29
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    IT DID, really. Thanks for the comment. It worked for me too just now! So, I wrote about it since I'm going to need to look back at my instructions here in the future I'm sure! https://askubuntu.com/a/1271252/327339 – Gabriel Staples Aug 30 '20 at 07:58
  • I'm having exactly this problem, and am likely to try the fix proposed here. I did find this link, which indicated some people are having trouble with iwd in other ways. Is it working well for you folks? https://discourse.ubuntu.com/t/call-for-testing-improved-wifi-via-iwd/17795/58 – Vultan Sep 24 '20 at 11:06
  • @Vultan My experience has been quite good. I've had some random disconnects earlier, but I think that upgrading to kernel 5.8 fixed that (at least on Manjaro). I've only been using WPA2 personal networks, though. – Jacajack Sep 24 '20 at 12:24
3

New info. as of 25 Aug. 2021:

As of the latest automatic updates on Ubuntu 20.04 today, 24 Aug. 2021, my answer below broke my wifi completely and I had to undo it and go back to using wpa_supplicant.service instead of iwd.service. See my new Q&A here: Ubuntu 20.04 WiFi “No Networks” after latest automatic update today. Your results may vary. Try what I present below anyway, and respond whether it works in the comments, and what system you're using. If it temporarily breaks your system too, it's always really easy to undo, so just try out my answer below anyway and report back.

Original answer from 30 Aug. 2020:

Holy smokes! How infuriating! I just lost 3 hrs today trying to install and set up my brand new TP-Link Omada AC1200 Gigabit EAP225-Outdoor wireless Access Point (AP) (works awesome, by the way!--I get 10~20Mbps download and upload internet at the park 100 yards away now!) all because my stinking Ubuntu 20.04 machine wouldn't connect to the 2.4GHz hotspot during setup.

A google search for "ubuntu cannot authenticate on 2.4ghz" led me to this question as the #1 hit, and sure enough, this answer by @Jacajack solves my problem! I think this solution deserves a more thorough response, however, so that's what I'm adding here.

First off, let me say this:

  • My Ubuntu 18.04 machine worked perfectly on both the 2.4Ghz and 5Ghz hotspots.
  • My Android phone worked perfectly on both the 2.4Ghz and 5Ghz hotspots.
  • My Ubuntu 20.04 machine worked perfectly on the 5Ghz hotspot, but would repeatedly, again and again and again and again, ask for my hotspot connection password every 30 seconds or so when trying to connect to the 2.4Ghz hotspot, and it would NEVER successfully connect to it!

I thought it was my motherboard or wifi card going bad, since I can connect to my other networks just fine, but it turns out it's just an Ubuntu 19 / Ubuntu 20 software problem.

So, this is the solution for:

How to connect Ubuntu 19.10 / Ubuntu 20.04 to a 2.4GHz wifi hotspot when it says it "cannot authenticate" again and again:

(Tested on Ubuntu 20.04 Aug. 30 2020). UPDATE 24 AUG 2021: the latest automatic updates on Ubuntu 20.04 today just broke my wireless from working! I had to UNDO the instructions below and go back from iwd.service to wpa_supplicant.service, as I describe in my Q&A here: Ubuntu 20.04 WiFi "No Networks" after latest automatic update today So, consider that as you try the instructions below. For the latest version of Ubuntu 20.04, with updates on or after 24 Aug. 2021, iwd.service may no longer work at all.

(Back to my original instructions):

These instructions are copied almost verbatim from @cadu_sg here, from 27 June 2020, so he/she deserves the real credit!

The solution, essentially, is to disable wpa_supplicant and replace it with iwd. I don't have the slightest clue what this means, but it works perfectly for me!

  1. Install iwd

     sudo apt update
 sudo apt install iwd

  2. Create this file inside your NetworkManager configuration files directory

     sudo nano /etc/NetworkManager/conf.d/wifi_backend.conf

  3. Copy and paste into this file the following content, then save the file:

     [device]
 wifi.backend=iwd

  4. Stop and disable the wpa_supplicant service (note that disabling it is persistent after reboots)

     systemctl stop wpa_supplicant.service
 systemctl disable wpa_supplicant.service

  5. Enable and start iwd service (note that enabling it is persistent after reboots)

     sudo systemctl enable iwd.service
 sudo systemctl start iwd.service

    CAUTION: If you see the below error after running sudo systemctl start iwd.service, stop here, undo the steps you've done thus far, and go back to using wpa_supplicant.service instead! Read my other answer here: Ubuntu 20.04 WiFi "No Networks" after latest automatic update today.

    Job for iwd.service failed because the control process exited with error code.
See "systemctl status iwd.service" and "journalctl -xe" for details.

  6. Restart NetworkManager service (this means you don't have to restart your computer for this to take effect--it just works immediately!)

     systemctl restart network-manager.service

Now, connect to the 2.4GHz wifi access point and it works perfectly! You type your password once, and it works just like it should! It continues working after reboots as well.

Thanks to all who contributed to this!

If anyone wants to explain what the heck I just did and what an iwd is and what wpa_supplicant is and why iwd works better, please do.

Note: my machine happens to be a high-end Dell Latitude 7490, but I don't think that matters. The access point is a TP-Link EAP225-Outdoor, which supports MU-MIMO, but I'm not entirely sure that matters either. My operating system is Ubuntu 20.04, which definitely does seem to matter. The entire problem seems to be in Ubuntu 20.04, not in my laptop hardware, and not in the EAP225-Outdoor access point.

Gabriel Staples
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1

I also stumbled upon this problem with Ubuntu 20.04 LTS and then got another problem with no visible network in wifi so the steps I made:

  1. run journalctl -n 1000 -u NetworkManager -u wpa_supplicant

  2. Found this:

<error> [1633498154.0549] iwd-manager[0x559330ce2d20]: failed to acquire IWD Object Manager: Wi-Fi will not be available (Error calling StartService>

  1. Then I run nmcli device

  2. Got this:

DEVICE  TYPE      STATE      CONNECTION         
enp2s0  ethernet  connected  Wired connection 1 
wlan0   wifi      unavailable  --     
lo      loopback  unmanaged    --
  1. Googled a bit and found this issue https://bugs.launchpad.net/ubuntu/+source/iwd/+bug/1938650
  2. Decided to try this out so I added the PPA to my system https://launchpad.net/~slyon/+archive/ubuntu/iwd+nm
sudo add-apt-repository ppa:slyon/iwd+nm
sudo apt-get update
  1. Added deb to sources.list by opening it with nano
sudo nano /etc/apt/sources.list

and pasting lines below at the end of the file

deb http://ppa.launchpad.net/slyon/iwd+nm/ubuntu YOUR_UBUNTU_VERSION_HERE main 
deb-src http://ppa.launchpad.net/slyon/iwd+nm/ubuntu YOUR_UBUNTU_VERSION_HERE main
  1. Then according to https://discourse.ubuntu.com/t/call-for-testing-improved-wifi-via-iwd/17795 I run
sudo apt install iwd
sudo gedit /etc/NetworkManager/conf.d/iwd.conf

Added lines below to the file

[device]
wifi.backend=iwd

and run

sudo systemctl mask wpa_supplicant
sudo reboot

After the reboot my wi-fi networks were now visible and I could even connect to my TP-link Archer C6 2.4ghz network without the problem

Vinnie Lecter
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0

The solution was to disable the TxBF, MU-MIMO setting on the access point, reboot it, the re-enable it and reboot again.

mark johnson
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