I was just on a phone call with a new customer who is setting up multiple retail locations.  The reason for the call was their backup network wasn’t working.  Whenever they tested the Verizon 4G LTE Wireless connected to Cradlepoint modem backup network, the phones would not be able to make or receive phone calls. Their IT staff was on the line and they were running Wireshark and grabbed a PCAP that seems to show that OnSIP at 199.7.175.101 was responding to their request with a “500 Server Error”.   The actual text was: SIP/2.0 500 Server Internal Error Warning: 399 sipalg “Internal Error” Call-ID: b876f6fb4aad25a55546217e07dd4f82 CSeq: 47 REGISTER From:…