voicemail problem

I’ve had two phones – w600i and v635. I used my w600i until a month or so ago, but I gave it to my brother and now I’m using the v635. I have a problem with the voicemail number. I’ve set the same number on the v635 as I had on the w600, but every time I try to dial it I can’t get through. I never had this problem with the w600i. What can I do about this? Any suggestions?

You can enter the voicemail number manually if you haven’t done so yet or you can try dialing your own number