Cisco 9800 wlan: Phones cannot connect to 2.4Ghz network

[ocristea88]

Hi, I have a problem with smartphones (android and apple) not being able to join a 2.4Ghz network. (Laptops can connect to 2.4) Phones can see the network, but after entering the PSK, they receive the message: unable to join the network. Also, I cannot even see the phone trying to connect on the controller side in order to run debug for the MAC address. When the wlan has both bands enabled, phones can connect. On the RF profile, the data rates look like this: 6Mbps mandatory, anything below is disabled, anything above is supported; 802.11n MCS Rates are all enabled. Controller is 9800 17.3.3, APs are 9120axi. Can someone please advise what might be the issue? Is 6Mbps data rate to low? - if so I would expect to see the phone trying to connect and see mismatch data rates, reason code 18 in radioactive traces.

Thank you

[JPavonM]

Do you have 802.11w-PMF enabled SSID? If so please disable it and check.

[ocristea88]

PMF is already disabled

[marce1000]

 - You can do client-debugging (mac based) or radiactive trace(ing) as it  is called on the 9800 platform which you can have analyzed with https://cway.cisco.com/tools/WirelessDebugAnalyzer/      You can also have a sanity check of the controller configuration with https://cway.cisco.com/tools/WirelessAnalyzer/ note however that for the 9800 (XE based) platform you need to feed it with the output of show tech wireless  .

 M.