Quick answer
If mobile data is not working, first confirm you have cellular signal and that Airplane Mode is off. Toggle cellular/mobile data off and back on, restart the phone, and check whether the problem affects every app or only one. Then verify your SIM or eSIM, data allowance and carrier status before resetting network settings.
Common causes
- Weak or unavailable cellular coverage.
- Mobile data disabled for the device or a specific app.
- SIM/eSIM, carrier account or outage issues.
- VPN or network configuration problems.
- Temporary software or radio errors.
Step-by-step fixes
1. Check signal and Airplane Mode
Move to an area where cellular coverage is normally available. Turn Airplane Mode on briefly, then off, and wait for the phone to reconnect.
2. Confirm mobile data is enabled
Open the phone’s cellular or mobile-network settings and make sure data is enabled. If only one app fails, check whether that app is allowed to use mobile data.
3. Restart the phone
A restart can refresh a temporarily stuck cellular connection without deleting data.
4. Check SIM or eSIM status
If the phone reports no SIM, invalid SIM or no service, follow your carrier’s supported SIM/eSIM troubleshooting. Avoid repeatedly removing a physical SIM if the tray or card appears damaged.
5. Check your carrier
Confirm that the account is active, the plan includes data and there is no known service outage or roaming restriction. Carrier-side issues cannot be fixed by repeatedly resetting the phone.
6. Disable VPN temporarily for diagnosis
If you use a trusted VPN, disconnect it briefly to see whether normal mobile data returns. Re-enable it afterward if it is not the cause.
7. Update software and carrier settings
Install trusted system updates when you have stable power and Wi-Fi. Menu names and carrier-update behavior vary by device and network.
8. Reset network settings only as a later step
A network reset can remove saved Wi-Fi networks and other connection preferences. Record anything important first and use it only after simpler checks fail.
Identify whether the problem is the phone, account or local network
Before changing advanced settings, compare what still works. If calls and texts work but mobile internet does not, focus on data settings, plan status and carrier configuration. If the phone shows no service at all, coverage, SIM/eSIM activation or a carrier issue becomes more likely. If another phone on the same carrier also has no service in the same location, check for a carrier outage before resetting anything.
iPhone-specific checks
On iPhone, Settings > Cellular lets you confirm Cellular Data is enabled and control cellular access for individual apps. Available options vary by carrier, region and iPhone model. If an app works on Wi-Fi but not cellular, check its individual cellular-data permission before making broader changes.
Samsung and Android-specific checks
On Samsung Galaxy phones, Mobile data can be checked from the Quick panel or under network/data settings. Samsung also provides a mobile-network reset on supported versions. Because menus vary across Android brands and software versions, use the reset description shown on your own device rather than following a menu path that does not match your phone.
Understand network reset before confirming
Network reset is less destructive than a full factory reset, but it can remove saved network configuration. Depending on the platform, that can include Wi-Fi passwords, cellular settings, VPN/APN information or Bluetooth/network preferences. Use it after simpler checks, not as the first action.
Roaming and dual-SIM checks
If the issue started while traveling, confirm whether your plan supports roaming and whether Data Roaming should be enabled for your situation. Charges can apply. On dual-SIM phones, also confirm that the intended line is selected for cellular data and that the line is active.
Quick diagnostic checklist
- Do calls and SMS still work?
- Does mobile data fail in every app?
- Does the problem occur in multiple locations?
- Is the correct SIM/eSIM or data line active?
- Is there a carrier outage, account restriction or exhausted data allowance?
- Did the issue start after changing carrier, SIM/eSIM, VPN or network settings?
What not to do
- Do not factory-reset the entire phone as a first step.
- Do not install unknown APN or “network booster” profiles.
- Do not share SIM PINs, account passwords or verification codes with untrusted support contacts.
When to contact the carrier or repair service
Contact your carrier when the account, SIM/eSIM, activation, outage or roaming status is unclear. Seek qualified device service if cellular connectivity stopped after a drop, liquid exposure or physical SIM-tray damage.
Related guides
If Wi-Fi also fails, see phone Wi-Fi disconnecting fixes. For an Android Wi-Fi connection with no internet, use our Android Wi-Fi guide.
FAQ
Why does Wi-Fi work while mobile data does not?
Wi-Fi and cellular data use different networks. Working Wi-Fi does not confirm that cellular coverage, the carrier account, SIM/eSIM or mobile-data settings are working.
Will resetting network settings erase photos?
It is not intended to erase personal photos, but it can remove saved network-related settings. Check your device’s current reset description before confirming.