Atheros wifi adapter keeps dropping in 26.04

[zpiatek]

I'm sharing an issue I submitted at https://bugs.launchpad.net/ubuntu/+bug/2154089.

Hello, I need to report a bug in K/Ubuntu 26.04 running on a Dell Inspiron 2350.

This PC runs fine with K/Ubuntu 25.10 and previous versions, but when I try 26.04, the wifi adapter will drop after a few second, then connect again. The cycle repeats.
A popup on the screen reads:

Network Management
Wireless Interface (wlp4so)
Authorization supplicant timed out.

I tried to file an apport when I ran ubuntu-bug but the connection problem won't allow it.

The wifi adapter is a Qualcomm Atheros QCA 95565/AR9565 wireless adapter. The kernel driver is ath9k.

I tried running a few commands when I researched the problem in https://launchpad.net/ubuntu, but didn't see one posted for 26.04.

Again, this runs fine on Kubuntu 25.10 and previous. Could this be a Linux 7 issue?

Any help would be greatly appreciated, and thank you in advance!

[Snowhog]

AI Overview

The "Authorization supplicant timed out" error on Kubuntu 26.04 (wlp4s0) usually indicates a failure between NetworkManager and the Wi-Fi driver to complete the WPA handshake, often caused by power management, driver incompatibility, or crowded channels. Key fixes include disabling Wi-Fi power saving, updating firmware, or switching from wpa_supplicant to iwd.

Immediate Fixes

• Disable Wi-Fi Power Saving: Create/edit /etc/NetworkManager/conf.d/default-wifi-powersave-on.conf and set wifi.powersave = 2 instead of 3.
• Restart NetworkManager: Run sudo systemctl restart NetworkManager.
• Forget and Re-add Network: Delete the network profile in KDE Plasma settings and reconnect to refresh security credentials.

Advanced Troubleshooting

• Switch to iwd Backend: If using wpa_supplicant, try switching to iwd for better stability on newer kernels.
• Check Kernel/Firmware: Ensure you are on the latest kernel, as chipset support (especially MediaTek) changes frequently.
• Disable 802.11k/v/r: If using a high-end router, disable fast roaming (802.11r) or BSS transition management (802.11v) as these can cause premature disconnections.
• Access Point Settings: Ensure your router is not forcing 5G or 6G channels that the card handles poorly, and ensure the router channel is not highly congested.

If you are using a MediaTek card, you may need to look into updating firmware-sof-signed or installing specialized firmware packages, as they are often prone to this specific error.

[zpiatek]

I have disabled Wi-Fi Power Saving by setting the value to 2. I then restarted the NetworkManager. I also deleted the network profile and then added it back in.
No change.