i have a mox6 and have tried plugging a microphone and a guitar into it. I can hear it fine through my monitors but when i go to record in song mode it just doesn't record.

And it will not. In order to record audio through a MOX or MOXF you need to connect to a computer. The MOX and MOXF include a built-in audio interface for either a Windows or Macintosh computer. You will need to connect to a computer using a USB cable. You'll need to download and install the Yamaha Steinberg USB driver for the computer type and operating system.

The recorder in the MOX/MOXF is a MIDI sequencer, it does not record audio, at all.

They do not record audio internally. Your MOX came with a free copy of Cubase AI which is a Digital Audio Workstation (DAW) software package that will allow you to record your guitar and your vocals (separately). See the Quick Guide section of your Owner's Manual (starting on page 50).

thanks so much.i got the synth in a shop second hand, so it didn't include cubase.