I am trying to figure out how to properly configure out voip provider failover IP. They do authentication by source IP address so we direct all our SIP traffic out a specific IP on our side which works great. They have 2 different data centers with separate IPs. So on the General tab for the voip provider we have SIP server host IP set. The authentication ID field is left blank since there is no ID or password. The issue comes in that when we try to add the secondary IP as a second provider we get a message saying "A line with this authentication ID already exists" and that ID is blank..... Is there a different way i should be going about this to try to configure redundancy in VOIP provider IPs?