Failover not working

I have two pbx that I have trunked using iax. I have it to where if they dial the phone number of the remote site it goes out through the iax trunk. It works pretty good but I wanted to set up a fail over mechanism in case the network went down so it could use the zap channels. The reason being sometime the network connectivity between the two sites get curtailed but it never seems to resort to the zap channels. Here’s there relevant excerpt of the dialplan

exten => 5551234,1,Dial(IAX2/user:pass@, 45,Tt);Remote site
exten => 5551234,102,Dial(Zap/g0/${EXTEN});fail over to Zap (not working)

Any help will be greatly appreciated

What comes up in the CLI ? If the remote asterisk box acts as if it is taking the call then you will run in to. You may want to ring the first location for 10 seconds and then roll over to the zap trunk.