Optical output on contour box out of sync

I use an HDMI cable to my Samsung tv and I connected an optical cable from the cox stb to my receiver, but the audio is slightly out of sync. If I run the optical cable from the tv it’s fine, but it won’t output 5.1 that way. That’s why I wanted to run the audio from the cox box. I tried the delay settings on my receiver but it made it worse. Are there any hidden settings on the cox stb for this?