Full bars and nothing loads
Two different faults get described the same way. In the first, the phone shows a signal and a data indicator but nothing loads, which usually means the connection exists and something is refusing to carry your traffic: a data limit, a restriction, a broken private DNS setting, or a network problem beyond the phone. In the second, there is no data indicator at all, which points at the SIM, the network registration or the radio settings.
Working out which one you have takes ten seconds and saves most of the time people spend on this.
Which fault do you have
| What you see | What it usually means | Where to look first |
|---|---|---|
| Signal bars, data icon, nothing loads | Connected but traffic is blocked | Data limits, private DNS, VPN, restrictions |
| Signal bars, no data icon | Not registered for data | Mobile data toggle, APN, roaming |
| No signal at all | No network registration | SIM, airplane mode, network selection, coverage |
| Works on wifi only | Data specifically disabled somewhere | Data saver, per-app restriction, limit reached |
| One app fails, the rest are fine | Not a network fault | That app's own permissions and storage |
| Stopped after an update or a new SIM | Configuration reset | APN and network reset |
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The order to work through it
- Toggle airplane mode, then restart This re-registers the phone with the network and fixes a genuine majority of cases, particularly after travelling or a long period on wifi.
- Check mobile data is actually on, and data saver is off Both live in the quick settings panel and both get toggled by accident. Data saver blocks background data and breaks some apps completely.
- Look for a data limit you set and forgot Android can be told to cut mobile data off at a monthly figure. When it triggers, the phone behaves exactly as though the network has failed. The warning and limit are in the data usage settings.
- Turn off any VPN, and check private DNS A VPN that will not connect can leave traffic going nowhere, and a private DNS hostname that is wrong or unreachable blocks every lookup while showing a full signal. Set private DNS to automatic while testing.
- Check roaming, if you have travelled or changed network Data roaming off is correct at home and is why the data stops the moment you cross a border. Some domestic networks also route through partners that count as roaming.
- Try the SIM in another phone, or another SIM in this one This is the single most informative test available and it takes two minutes. It separates a phone fault from a SIM or account fault immediately.
- Reset the APN to default In the SIM settings, under access point names, there is an option to reset to default. This restores the configuration that an update, a cleaner app or a bad tutorial removed.
- Reset network settings, as the last step before the network This clears wifi passwords, paired Bluetooth devices and mobile settings together. It fixes stubborn cases, and you will need those wifi passwords afterwards.
What an APN is, and when to touch it
An access point name is the short configuration that tells the phone how to reach the network's data service. Phones fill it in automatically from the SIM, and in normal use nobody should ever need to see it. It matters in three situations: a SIM from a smaller network that piggybacks on a larger one, a phone bought in another country, and an update that lost the configuration.
The safe procedure is to reset to default first and only then, if that fails, enter the settings published by your own network on its own website. Copying an APN from a forum or a video is how people end up with data that works for a week and then breaks in a way nothing explains, and it is worth noting that no APN setting has ever made a connection faster than the network allows.
Apps that tell you something true
Speedtest by Ookla. The standard measurement, and its history is the useful part: a record of what this location normally gives you turns a vague complaint into a comparison.
PingTools. Ping, traceroute and DNS lookups on a phone. If names fail but numeric addresses work, the fault is DNS, which is a five-second diagnosis with this.
Network Analyzer. Shows the connection details the settings screens hide, including which DNS servers are actually in use.
Network Cell Info Lite. The real signal figures rather than the bars, plus which cell and which technology you are attached to. The bars are a decoration; these numbers are not.
Signal Strength. A smaller version of the same idea, with a widget that logs signal over time, which is how you prove a problem happens only in one room or at one time of day.
Network Signal Info. Reports both mobile and wifi in one screen with a clear history graph, useful for showing a provider what has been happening.
My Data Manager. Tracks usage against your allowance and per app. The app that quietly used the whole allowance in a week is findable here.
GlassWire. Shows which apps are using data as they do it, which is the quickest way to find a background sync that has gone wrong.
Datally. Lightweight data usage control from Google, including blocking background data per app without the side effects of the system-wide saver.
NetGuard. A firewall that needs no root and can block mobile data for specific apps. Deliberate control, and also a common self-inflicted cause of one app having no internet.
When it is not the phone
If another phone on the same network in the same place also has no data, stop. Check the provider's status page, and remember that outages are often local and brief enough not to be announced. Unpaid bills, a SIM deactivated after long inactivity and a newly activated eSIM that has not finished provisioning all produce the same symptoms as a broken phone.
The other genuine external cause is the phone not supporting the bands the network uses, which appears after buying a handset abroad or moving to a different country. The phone works, the SIM works, and the data is slow or absent in places where everyone else's is fine. Nothing in the settings fixes that.
Decide first whether you have a signal without data or no signal at all. Airplane mode, restart, then limits, DNS and roaming. Swap the SIM into another phone before blaming the handset.
Frequently asked questions
Why does data work on wifi but not mobile?
Almost always something specific to mobile data: the toggle, data saver, a monthly limit that has triggered, roaming being off, or a per-app restriction. Check the data usage settings for a limit before anything more elaborate.
What does resetting network settings actually delete?
Saved wifi networks and their passwords, paired Bluetooth devices, and mobile network preferences including any manual APN. No photographs, apps or messages are touched. Write down the wifi password before doing it.
My phone shows full bars but nothing loads. Why?
Bars show radio signal, not whether data is flowing. A full signal with no traffic points at a data restriction, a broken private DNS setting, a VPN that failed to connect, or congestion on a cell that is signalling strongly to everyone nearby.
Should I enter the APN settings I found online?
Only from your own network's own published page, and only after trying reset to default. Values from forums and videos are frequently for another country or another network, and a wrong APN produces intermittent faults that are hard to trace back.
Do network booster apps work?
No. Software cannot increase the strength of a radio signal. The apps that claim to either do nothing or simply toggle the radio, which you can do yourself with airplane mode.
Data stopped the day I got a new SIM. What is different?
New SIMs sometimes need the phone restarted to pick up the configuration, and a SIM from a smaller provider may need an APN that the phone does not know. Restart first, then reset the APN to default, then use the provider's published settings.
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