Won't Record. Why?

I hit the ‘record’ button, the bar and the arrow turn red, I start the music, but the bar won’t move. I updated this morning, and this has happened before, and it’s VERY frustrating. It was fine for a while, but it’s started this again. WHAT’S GOING ON?! I’m no experienced pod-caster, I’m just trying to record some music. Will someone please help?