After upgrading to Roon 1.3, I no longer get sound when networked through HQPlayer (either choosing System Output or into an External USB DAC in HQPlayer settings).
Both programs have no trouble playing on their own (for either system output or through a USB DAC).
Other users have encountered a similar problem and appear to have fixed it by entering a fixed IP like “127.0.0.1” instead of “localhost”. If that doesn’t solve your problem let me know and we’ll see if we can help.