Hi,

Here is a link that shows how to perform a 'soft' (wipe cache partition) and a 'hard' (master reset with hardware keys) reset on your phone.

Perform the soft reset first and see if it resolves your problem, if not perform a hard reset.

A soft reset does not erase any of your apps or data

Be aware that a hard reset will erase all your downloaded apps and user data. It will restore your phone to a factory default condition. It will be like when you first bought it.

Before you perform a hard reset ensure that the battery is charged.

Do not leave the charger connected when you perform a hard reset.

Remove the SD card (if there is one inserted).

https://support.t-mobile.com/docs/DOC-94...

Be patient, it takes a few minutes.