If the playback button is unresponsive, this might be caused by an internal error of the application. To fix this, you should probably download and use the latest version released. You can obtain a download link for this from the review page of the application from Software Informer.
This problem might be caused by the ASIO setting. To fix this problem, visit the following official website in order to download the appropriate drivers. Also, try using the DS setting in order to check if there is a problem with the application or only ASIO.