Focusrite Vocaster One

I’m using it in GarageBand on Mac, with all the correct cables and the Røde NT1-A mic it came with.
It either only sends a very weak signal, even when you sing super close to the mic. Or when you turn up the input volume on the Vocaster, the recording immediately distorts (and is still very weak).
When you do try to record a track it frequently cuts out after a few bars. So you get five to ten seconds with sound and then just silence.