I'm not sure what you mean here. Are you trying to deactivate Touch ID, or are you wanting to reactivate it? The title of your post seems to indicate Touch ID stopped working, so I'm thinking you want to reactivate it, but I'm not sure at this point. Also, are you able to unlock mSecure by manually entering your password using the device's keyboard to type in the characters?
@Arturo I'm not sure what you mean here. Unless you made some changes to something on your device, the fingerprint unlock feature shouldn't have been disabled. Regardless of how it was deactivated, you should see the option to re-enable it in mSecure's Settings.