Thank you for your post.
Please make sure that you have the latest version of Max2Play, if not please download and burn new image.
For the first issue, please try to Follow the bellow steps:
1. Please try to download the latest official version of LMS, which is Logitech Media Server v7.9, and reinstall LMS.
2. if the the problem has not been solved, we recommend you to post this question on the SlimDevices forum :http://forums.slimdevices.com
Regarding the second issue, please follow the below steps:
1. You do not have any plugin in the LMS that converts the audio file format.
2. Make sure you are using the default settings in the audioplayer webpage, you can check the bitrate from the debug section in audioplayer page.
When you are using the HDMI, the audio sample rate is limited to max 48 KHz. You can check the following website for testing: