Acrobits 5.4.1 works great for me when calling from wifi. But there's a bug when I try to make an outgoing call from Verizon 3G/LTE: if the call is unanswered, the call will drop rather than going to voicemail. If anyone is aware of any configuration setting I can change to fix this? Acrobits tech support suggested trying various combinations of setting NAT Traversal to Auto/Off/Stun and Discover Global IP to Internal/External, but none of those six possible combinations worked.