got my watch yesterday. can't make phone calls using watch. displaying called failed

Yes. iOS 8.4 has fixed the issue. After the update yesterday, I'm now able to make and receive calls on the Apple Watch.

actually you dont have to unpair it, just reset the network setting.

before i begin i try to make a call from facetime its work. Then i reset the network setting without unpair and pair it.

it seems the problem with ordinary call cause by phone or service provider.