That is strange.
I suppose both of the Wifi´s are home based. I mean that you can access the router and stuff like that.
Maybe there is a kind of firewll on the router blocking the incoming calls?
If it is not, try to have another accesspoint. As using video uses some bandwidth, so it could be limited.
i use it with my mum in Belgium, and we don´t have problems. It worked from the first time.
Here is some data I just found on anther website, hope this helps:
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The most common cause of FaceTime calls not being received is that the destination device is simply not within Internet-connected Wi-Fi coverage. The calling user receives no notification of this—the outgoing call simply rings as if it is not being answered, while the called user never hears a ring. He or she will receive a missed call notification only after the FaceTime call stops ringing.
This problem also commonly occurs at public Wi-Fi hotspots where users may not be logged in or their logins have timed out. Many public Wi-Fi hotspots require a separate login through a web browser page in order to actually access the Internet. In this case, even though the iPhone or iPod touch displays the Wi-Fi symbol, the device cannot be reached by the FaceTime servers until the user has logged into the Wi-Fi hotspot service.
Firewalls and certain router configurations can also prevent FaceTime calls from being received. This applies to most corporate and some school firewalls. If you’re having this problem with your own home router, see the section later in this article on home network issues.
This issue is most commonly caused by network configuration problems. This can include a firewall that blocks FaceTime, or simply a home router that is incorrectly configured or does not support the protocols necessary for FaceTime. See the section below on troubleshooting home network issues for more information.
This problem can also occur if you are trying to call an e-mail address that is also configured on your own device in your FaceTime preferences. In order to call another FaceTime address, it must have an e-mail address that is not configured on the device you are calling from.
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regards,
David