Try the following to resolve your issue:
Uninstall, re-download and re-install the latest version of the app from www.Bose.com/soundtouch_app. On some devices, the app may be unable to properly install the update over the existing version. If this occurs, the app must be re-downloaded and re-installed. You will need to log in to the SoundTouch account upon opening the the new install. Network credentials, music services and library settings will not need to be set up again as the information pertaining to these configurations will be retained.
When reinstalling the app, be aware of any pop-up messages that appear concerning the SoundTouch App and SoundTouch Music Server. Depending on the firewall or security software installed, if an "always allow" option is available, be sure to select this option; Otherwise select the option that allows for firewall access over any option that denies, restricts or limits firewall access.