One UI 9 Wi-Fi Not Working: 6 Fixes to Try

[tldr] Quick answer: if Wi-Fi or mobile data died after the One UI 9 update, try these in order: turn off Wi-Fi 7 mode in Connectivity Labs (the fix several Z-series owners report), forget and rejoin the network on the 2.4 GHz band, remove and reinsert the SIM, then Reset network settings. A full factory reset is the last step, not the first. Samsung has not confirmed a cause or shipped a permanent patch as of 9 November 2026. [/tldr]

[howto_callout type="tip"] Bookmark this page (🔖): the update is rolling out in phases, so your other Galaxy may hit this next week. Keep the steps handy. [/howto_callout]

What is actually happening

One UI 9 (built on Android 17) started rolling out in September. Over the first week of November, owners on Samsung Community and Reddit reported phones that connect to Wi-Fi and immediately drop, show “connection failure”, lose mobile data, or lose the SIM entirely. Reports span the S series, Z Fold/Flip and A series, which points at software rather than one bad batch of hardware.

Two details worth knowing:

Not every updated phone is affected. Getting One UI 9 is not a guarantee of trouble.
This is the second wave of complaints. Battery drain was reported earlier after the same update.

First, confirm you are on One UI 9

Settings → About phone → Software information → One UI version

If it says 9.0, you are in the affected rollout. Also check Settings → Software update → Download and install: Samsung sometimes ships a small patch that fixes the radio behaviour without changing the version number.

Fix 1: turn off Wi-Fi 7 mode (the one that works most often)

Several Z Flip and S-series owners report that disabling Wi-Fi 7 stops the connect-then-drop loop. Wi-Fi 7 (802.11be) is new, and the driver is the most likely place for a regression.

Settings → About phone → Software information
Tap Build number seven times to unlock Developer options
Settings → Developer options → Connectivity Labs (or “Wi-Fi developer options”)
Turn Wi-Fi 7 mode off, then toggle Wi-Fi off and on

Everyday browsing, streaming and calls are unaffected by this. You lose nothing except the newest standard.

Fix 2: forget the network and rejoin on 2.4 GHz

One S24 Ultra owner reported 5 GHz failing while 2.4 GHz worked normally.

Settings → Connections → Wi-Fi → tap the network → Forget
Reconnect, and if your router broadcasts both bands, pick the 2.4 GHz SSID
If that works, the problem is band-specific, not your whole radio

Fix 3: SIM and mobile data checks

Power off, remove the SIM tray, reinsert the SIM, power on
Settings → Connections → Mobile networks → Access Point Names → menu → Reset to default
Turn VoLTE and Wi-Fi Calling off for a day — both rely on the same radio stack that is misbehaving

If another SIM in the same slot works, the problem is your carrier profile, not the phone.

Fix 4: Reset network settings (keeps your data)

This wipes saved Wi-Fi networks, Bluetooth pairings and APN settings — nothing else. Photos, apps and accounts stay.

Settings → General management → Reset → Reset network settings → Reset settings

You will need to re-enter your Wi-Fi password afterwards.

Fix 5: check Safe mode to rule out an app

Hold power + volume down → long-press Power off → Safe mode. If Wi-Fi behaves normally in Safe mode, a third-party app (VPN, firewall, “network booster”) is the culprit. Uninstall anything that manages connectivity, then reboot.

Fix 6: wait for the patch, or escalate

Keep checking Settings → Software update. Samsung usually pushes a stability patch within a few weeks of widespread reports.
If you bought the phone locally and it is unusable, a Samsung service centre can reflash the firmware — cheaper and less risky than a factory reset performed blindly.
Back up with Smart Switch before any reset, so you keep photos and chats.

The order that saves the most time

Wi-Fi 7 mode off (2 minutes)
Forget and rejoin on 2.4 GHz (2 minutes)
SIM reseat + APN reset (3 minutes)
Reset network settings (2 minutes)
Safe mode test (5 minutes)
Service centre or patch (waiting)

Skip the factory reset until all six are done. Most people who reset their phone for this end up with the same bug on a clean install.

FAQ

Is this a hardware fault?

Unlikely. The reports cross several models and started right after a software update, which is the classic signature of a radio firmware regression.

Will a factory reset fix it?

Sometimes temporarily, but the bug travels with the firmware. If the build is affected, a clean install can bring the same failure back after the first update.

Does turning off Wi-Fi 7 slow my connection?

No for normal use. Wi-Fi 6 (and even 5) already exceeds most home broadband speeds. You only lose theoretical throughput on a Wi-Fi 7 router.

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