Restart your device. If restarting doesn't work, switch between Wi-Fi and mobile data: Open your Settings app and tap Network & internet or Connections. Depending on your device, these options may be different. Turn Wi-Fi off and mobile data on, and check if there's a difference.
Your phone may not be connecting to cellular data because the carrier settings need to be updated, the phone is connected to a Wi-Fi network, or your SIM card is dislodged.
Reset network settings
This is an extremely important solution to follow when cellular data fails to work on your iPhone. Go to Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings. Once this completes, cellular data should work like a charm.
Update your software or check your data
If you're still having problems connecting to the internet using mobile data, make sure you've updated your device with the latest software. You may also have reached your data allowance limit, which will stop you from using more mobile data.
Check and make sure that your phone isn't on Airplane Mode — you can do this by checking your phone's control center and making sure the "Airplane" icon is turned off. You could also try re-inserting your SIM card into your phone. This resets your phone's connection to the SIM card.
Mobile data not working properly on a Samsung smartphone is often the result of a specific setting or mode, such as Airplane Mode, being enabled or the incorrect preferences being selected after switching to a new mobile carrier.
Causes of Mobile Data Not Working
A no-data connection error can result from a basic software glitch, damaged hardware, or even a system-wide outage that renders the entire mobile network unavailable. Below are some proven solutions to get your mobile phone's cellular data working again on iPhone and Android.
Turn cellular data off and then back on again. Go to Settings, then tap Cellular or Mobile Data. If you're using an iPad, you might see Settings > Cellular Data. If you're traveling internationally, make sure that your device is set up for data roaming.
Check your mobile data usage: If you have a limited data plan, you may have reached your data limit for the month. You can check your data usage by going to Settings > Cellular and scrolling down to "Cellular Data Usage". Restart your phone: Sometimes a simple restart can help fix minor issues with your phone.
Resetting network settings on an iPhone or Android smartphone will not delete any mobile carrier functionality or account information. The process resets any changes to mobile preferences you may have made since you activated your device.
It's important to know how to turn data roaming on and off on your phone. Turning it off ensures you're not hit with large bills for your data and turning it on allows you to access the internet when traveling abroad. To enable or disable data roaming on Android: Open the Settings app.
Eject, clean, and reinsert your SIM card
Moving forward, you may need to clean and reinsert your SIM card now to fix the “4G not showing” issue. If your SIM card is dirty or not positioned very well, it can hinder you from enjoying the best network connection.
Restart phone
Your Samsung device may be having problems with the operating system, and this leads to cellular data failure. The simplest solution to this is to restart the phone and wait for the error to be fixed. This way, you can check if you can connect to the internet again.
1) Restart your device
The best way to disperse a minor software glitch causing a network connection error is by restarting the device. Don't use the Reboot option; switch off the device and boot it up after a minute or two. This step should bring about a reset to potentially counter the error.
It's possible that your device is having trouble finding your network, and you have to select it yourself. Go to Settings> Connections > Mobile networks > Network operators. A list of network providers should show up. Select yours and see if this fixes your problem.
There are several reasons why Android phones say "no service", but there are common ones. A few reasons are when the SIM card is not properly inserted or may not be working. Another reason might be your phone's system has been a problem.
You can limit your data usage when abroad by turning off data roaming. You'll then not be able to access the internet using the mobile network when abroad. You can still use Wi-Fi even though data roaming is turned off.
You can usually tell when your phone is roaming, because instead of your usual network listed at the top of your phone, another network partnered with your carrier will be listed in its place.
While each carrier will offer different international roaming rates, you can almost always expect to pay more for consuming data outside the country. These additional fees means that you need to be conscious of how your are being billed while overseas.