More info would help. What is the keyboard..... how are you listening to the music (via headphones, into a mixer, does it have built in speakers?) Making electronic music can be pretty complex (you route audio outs into a mixer, into the computer, into a DAW then back out, at the same time you are worried about midi in and out and syncing the audio) and everything has lots of "options" (insert, switches which can #$%** the whole thing up). So, when a problem arises, check one thing at a time. For example, if you are listening via a mixer and your sound dies..... does your keyboard make sounds with headphones? If it makes no sound when you play it..... does it make sound when the onboard demo tune is played (I was convinced I had done everything right, but could get no sound out of module.... until I played the demo tune and it blasted sound into the room.... made me go back to the drawing board and find the problem.)
So, more info and start with checking one thing at a time.
Take Care