A lot of networks do this, it's not just Verizon. We've seen invites disappear at many different networks like hotels and different mifis. As well as registrati

A lot of networks do this, it's not just Verizon. We've seen invites disappear at many different networks like hotels and different mifis. As well as registrations never go through on some. That said, this and poor implementations of sipinspect on routers appear to be the Achilles heal of SIP.