User Guide

Table Of Contents

Q: Why do I get the error message Expired certificate or Certificate

not valid yet when I am installing a downloaded application?

A: If Expired certificate or Certificate not valid yet is displayed, even if the

certificate should be valid, check that the current date and time in your device are

correct. You may have skipped the setting of date and time when starting the device

for the first time, or the mobile network may have failed to update these settings

to your device. To resolve this, select Menu > Settings and Phone > Phone

mgmt. > Factory settings. Restore the factory settings, and when the device

restarts, set the correct date and time.

23. Green tips

Here are tips on how you can contribute to protecting the environment.

Save energy

When you have fully charged the battery and disconnected the charger from the

device, unplug the charger from the wall outlet.

You do not need to charge your battery so often if you do the following:

● Close and disable applications, services, and connections when not in use.

● Decrease the brightness of the screen.

● Set the device to enter the power saver mode after the minimum period of

inactivity, if available in your device.

● Disable unnecessary sounds, such as keypad and ringing tones.

Green tips