Sony Xperia XZ1 Manual page 17

Only downloaded apps can be fully uninstalled.
4. Touch and hold the app icon until the device vibrates.
5. In the menu that opens, tap

Update your device to ensure that you have optimal performance and the latest
enhancements.

Perform a factory data reset. This is sometimes the best solution if your device stops
functioning properly, but note that it will delete all personal content saved on the
internal memory of your device. Make sure to back up data that you want to keep.
An app isn't working
Xperia™ XZ1 Dual SIM support overview
If an app on your device isn't working properly, try these actions one after the other. Verify
after each action whether the problem was solved before trying the next one.
Downloaded apps that you have not downloaded from Google Play™ may not be fully
compatible with your Xperia™ device. If the following actions do not solve the issue,
contact the developer of the app for further information.

Force the app to close down, and then open it again.
To force stop an app
1. Find and tap Settings > Apps & notifications > App info.
2. Find and tap the app that you want to stop.
3. Tap FORCE STOP > OK.

If the app requires an internet connection, make sure that your device has an active
internet connection (Wi-Fi or mobile network), and that Airplane mode is turned off.
To turn off Airplane mode
Read about how to update and find latest software version.
> OK.