Im using elastix 1.0-17 and i have 3 grandstream gxp2000 phones. One phone works perfectly with no problems. I can call in and call out with no problems. The other 2 phones act like they arent even there. If i try and call the extension assigned to them i get the unavailable message, but yet i can call from them to the working phone and it rings. The phones show they are registered but i cant call them. Any ideas?