One UI 9 Broke Wi-Fi or Mobile Data on Your Galaxy? Here’s What to Try

Samsung’s stable One UI 9 update was supposed to be the easy part. After months of beta testing, Android 17 finally landed on Galaxy phones in the U.S. this fall. Now a growing number of owners say the update has quietly broken the one thing a phone can’t do without: staying connected.

Reports collected on Samsung’s Community forum and Reddit, and written up this week by Android Police, Android Headlines and SammyGuru, describe Galaxy phones that drop Wi-Fi, refuse to join a home network, lose mobile data or, in the worst cases, stop seeing the SIM card altogether. As of Friday, Nov. 6, Samsung had not publicly acknowledged the problem.

If your Galaxy has been acting up since the update, you’re not imagining it. Here’s what’s going wrong, which phones are showing it, and the fixes worth trying before you factory reset anything.

What One UI 9 is breaking

The complaints fall into four buckets, and Wi-Fi is by far the biggest one.

• Wi-Fi that won’t stick. Phones disconnect after a while and throw a “Connection failed” error. Some will join other saved networks but not the one at home. One Galaxy S24 owner said a restart got them back online, only to be kicked off again shortly after.
• 5GHz trouble. A Galaxy S24 Ultra user reported the phone connects fine on a 2.4GHz network but won’t hold a 5GHz one.
• Mobile data and Wi-Fi calling. A Galaxy Z Fold 7 owner on T-Mobile couldn’t connect to their home 5G, and another Fold 7 user said T-Mobile Wi-Fi calling stopped working even though Wi-Fi itself was fine.
• Missing SIM cards. The rarest but scariest one. A Galaxy A56 owner said the phone stopped detecting any SIM, and Samsung’s own built-in diagnostics couldn’t find either of the two cards installed.

One SammyGuru writer hit the Wi-Fi drops on their own Galaxy S26 Ultra, which tells you this isn’t just an older-phone problem.

Which Galaxy phones are affected

Nobody has a definitive list, and that’s part of the frustration. Android Police put it bluntly: “almost all popular Galaxy devices seem to be affected.” Here’s what owners have reported so far, pulled from the three outlets that tracked the complaints:

A little perspective helps here. These are user reports, not lab-verified failures, and they clearly don’t hit everyone. Android Headlines editor Kristijan Lucic noted he’s had no issues on a Galaxy Z Fold 8 that shipped with One UI 9 out of the box. Still, the spread across flagships, foldables and the midrange A series suggests something in the update itself rather than one bad batch of hardware.

How to fix One UI 9 Wi-Fi and data problems

There’s no single fix that works for everyone yet. These are the steps owners have tried, in the order we’d attempt them, starting with the ones that cost you nothing.

1. Restart, or toggle Airplane mode. This brings Wi-Fi back for a lot of people. The catch: several users say the connection drops again within a few hours. Treat it as a stopgap.
2. Forget and rejoin your home network. Since some phones balk only at one specific network, removing it and signing back in is worth a minute. If your router broadcasts 2.4GHz and 5GHz under separate names, try the 2.4GHz band while you wait for a patch.
3. Reset network settings. Go to Settings > General management > Reset > Reset network settings. This wipes saved Wi-Fi passwords and Bluetooth pairings, so have them handy. Results are mixed: it helped some users and did nothing for others.
4. Reset network and Bluetooth together. One Galaxy Z Fold 8 Ultra owner said resetting both fixed it outright. Another said the same combination didn’t help. Your mileage will vary.
5. Reseat the SIM. If your phone says there’s no SIM, power it off, pop the tray and reinsert the card. Some users got their signal back this way; others didn’t.
6. Try Safe Mode. A Samsung Community moderator suggested booting into Safe Mode to rule out a third-party app. Hold the power button, then long-press Power off to see the Safe Mode option.

Hold off on a factory reset. A Samsung moderator floated it, but at least one user said wiping the phone still didn’t bring mobile data back. That’s a lot of setup time to spend on a coin flip.

If Wi-Fi calling is the only thing broken

T-Mobile customers who’ve lost Wi-Fi calling should check that it’s still switched on in the Phone app’s settings after the update, then toggle it off and on. If calls still won’t route over Wi-Fi, contact the carrier so the outage is logged on their side too. That paper trail matters if the fix ends up needing a carrier-side change.

When will Samsung fix it?

That’s the open question. Samsung hasn’t commented on the connectivity reports, which is a bit odd given how quickly it moved on an earlier One UI 9 bug that left some Galaxy S26 Ultra owners stuck on the setup screen. Android Police is hoping the November firmware update brings a fix, but nothing has been confirmed.

Our take: this is the kind of bug Samsung can’t sit on for long. Wi-Fi drops are annoying. A phone that stops seeing its SIM can’t make or take a normal call at all. If you haven’t installed One UI 9 yet and your current software is working fine, there’s a reasonable case for waiting a couple of weeks to see whether a patch lands first.

If you’re already affected, the most useful thing you can do is report it. Open the Samsung Members app, tap Support, then Error reports, and describe the issue. Samsung’s engineers prioritize what shows up in volume, and right now the forum threads are doing most of the talking.

We’ll update this story when Samsung responds or a fix starts rolling out.

Sources: Android Police, Android Headlines, SammyGuru. Photo by Amanz on Unsplash.