Seeing "No Service" or a missing signal icon on your Sony Xperia 1 VI is a real roadblock. It cuts you off from calls, texts, and mobile data right when you need them most. The good news is that this is almost always a software or settings issue you can fix yourself.
I'd start with the simplest fix first. Grab your phone and press and hold the Power button and Volume Up button together for about ten seconds. Keep holding until you feel the phone vibrate and the screen goes black, then release. This force restart clears out any temporary glitches in the system that might be blocking the cellular radio.
Check Your Basic Connection Settings
It sounds obvious, but it's worth a quick look. Swipe down from the top of your screen twice to open the full Quick Settings panel. Make sure the Airplane Mode icon isn't highlighted. If it is, tap it to turn it off.
While you're there, also tap the mobile data icon to turn it off, wait a few seconds, and then tap it again to turn it back on. This refreshes the connection to your carrier's network. If you're in a building, try stepping near a window or going outside, as the Xperia's antenna might be struggling with thick walls.
Reinsert Your SIM Card
A loose or dirty SIM card is a classic culprit for signal problems. You'll need the SIM eject tool that came with your Xperia 1 VI. Find the small pinhole on the left side of the phone's frame, insert the tool, and gently push to pop out the SIM tray.
Carefully remove the SIM card and take a look at the gold contacts. If you see any dust or debris, gently wipe them with a soft, dry cloth. Blow into the SIM tray slot as well to clear any dust. Then, reseat the SIM card firmly into the tray and push the whole tray back into the phone until it clicks.
Reset Your Network Settings
This is a powerful step that resets all your network-related configurations back to factory defaults. It will erase saved Wi-Fi networks and passwords, Bluetooth pairings, and any custom mobile network settings, but it won't touch your personal photos, messages, or apps.
To do this, open the Settings app and tap System. Then, tap Reset options. On the next screen, select Reset Wi-Fi, mobile & Bluetooth. Confirm your choice, and your phone will restart. After it boots up, you'll need to reconnect to your Wi-Fi and re-pair Bluetooth devices, but it often clears up persistent cellular issues.
Update Your Access Point Name (APN)
Your APN is like the phone's address book for connecting to your specific carrier's network. If these settings are wrong or outdated, you won't get service. Go to Settings > Network & internet > Mobile network > Advanced > Access Point Names.
You should see a list of APNs. If there's more than one, tap the one that corresponds to your carrier (it's often the selected one). If the settings look empty or incorrect, you can tap the three-dot menu in the top right and select Reset to default. For the most accurate settings, a quick web search for "[Your Carrier] APN settings 2026" or a call to their support will get you the exact details to enter manually.
Manually Select Your Network Operator
Sometimes your phone gets stuck trying to connect to a weak or incompatible tower. You can force it to search for and lock onto your proper carrier. Head back to Settings > Network & internet > Mobile network.
Tap on Network operators or Choose network. Your phone will scan for a moment. When the list appears, instead of leaving it on "Automatically select," tap the name of your actual carrier (like T-Mobile, Verizon, or AT&T). Wait for it to register. If it fails, go back and choose "Automatically select" again to let it retry the connection process from scratch.
Check for a Software Update
Sony periodically releases system updates that can fix bugs affecting the modem or radio software. Since the Xperia 1 VI launched on Android 14, ensuring you're on the latest version is important. Go to Settings > System > Software update.
Tap Check for update. If an update is available, download and install it. Make sure your phone is connected to Wi-Fi and has at least a 50% charge, or better yet, plug it into a 30W USB-PD charger. After the update installs and your phone restarts, check if your signal has returned.
Use the Phone Information Menu
Android has a hidden diagnostic menu that lets you see the raw status of your cellular radio. Open your Phone dialer app and type *#*#4636#*#* exactly. This should automatically launch the testing menu.
Tap on Phone information. You'll see a lot of technical data. Look for a dropdown menu that might say "Set preferred network type." Try changing this to another option, like "LTE/WCDMA" or "NR/LTE," then wait a moment. You can also try tapping the Turn off radio button, then the Turn on radio button to cycle the modem. This menu is advanced, so if you're unsure, just back out of it.
Consider Your SIM Card's Health
If you've had the same SIM card for many years, it's possible it has simply worn out or become deactivated by your carrier. The easiest way to test this is to put your SIM card into another unlocked phone. If that other phone also shows no service, the problem is with the SIM or your carrier account.
Call your carrier's support line from another phone. Ask them to check if there's an outage in your area or if there's any issue with your account status. They can often reprovision your line remotely. If the SIM is old, they can usually mail you a new one for free or you can pick one up at a store.
Review Installed Apps and VPNs
In rare cases, a recently installed app or an active VPN can interfere with cellular connectivity. Think back to any new apps you installed around the time the problem started. Try uninstalling them to see if the signal returns.
Also, check if you have a VPN running. Go to Settings > Network & internet > VPN. If you see a VPN profile connected, tap on it and select Disconnect. See if your mobile signal comes back immediately after disabling it.
