I would start out with a few seconds.....O.K maybe a minute

with you there. Once she goes in willingly give her a treat and lots of praise. Keep doing this and working your way up to a few minutes at a time. It may take a few days (or even longer) Then when you think she feels pretty comfortable with the door shut, then maybe try leaving the room or house for a couple minutes.
Make it extra comfy and maybe put a good stuffed-filled kong to keep her busy. When we leave the house we always keep the radio or TV on for them
Hopefully someone else has some more adivce for you!!
Good Luck!!