An app or an operating system glitch may prevent your phone from working.
A slow or disconnected internet connection can do the same.
What Causes a Phone to Freeze?

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There are several reasons why an iPhone, Android, or another smartphone might freeze.
The culprit may be a slow processor, insufficient memory, or a lack of storage space.
There may be a glitch or a problem with the software or a particular app.
Often, the cause will reveal itself with the corresponding fix.
Other times, a basic troubleshooting step may fix the problem without revealing the cause.
How to Fix a Frozen Phone
Reboot the iPhoneorAndroid.
As with most electronic devices, the first troubleshooting step is to turn the machine off and on.
Your phone is no different.
A restart or reboot may resolve a number of problems.
A flaw in the system software can cause sporadic and unpredictable problems.
Updating to the current version of iOS or Android resolves any systemic problems identified by the developers.
A bug in an app can affect a unit’s available memory or performance.
The best software developers maintain their software and publish periodic updates.
Configure your iPhone to automatically check for app updates or update apps on your Android smartphone.
Force the iOSorAndroid app to close.
On iOS, you shouldn’t need to quit apps often.
Use Android storage managerorfree up your iPhone’s storage spaceby deleting apps, photos, or videos.
Store videos and photos somewhere other than on the gear.
Videos take up the most storage space.
Delete problem iOSorAndroid apps.
If the phone frequently freezes after you open an app, remove the app.
Some apps are flawed or prone to crashes.
Reset the iPhoneorAndroid rig.
If you tried all the above steps and your phone still freezes, reset the rig.
On both iOS and Android, you canrestore from a previously made backup.
On iOS, the process involves eitherbacking up to iTunesor usingiCloud.
Visit a licensed repair facility.
If you have an iPhone,take the gear to an Apple storeorcontact Apple Support.
If you have an Android machine, contact either the phone manufacturer or contact your carrier for support.
Toclose a frozen Android app, reboot your equipment.
If that doesn’t work, force the Google Play Store to close.
Higher resolution videos require faster internet speeds.