Hi I have two asterisk servers with same config and the .xml file is configured to failover from server to server in case of failure with priority 0 and 1. When phone comes up they send “RegisterMessage” to ServerA and they get registered and works fine, When the server A goes down (I stop Asterisk service) the phones send the “RegisterMessage” to ServerB and things are fine. Now when the server comes back online the phone tries to register with a message “RegisterTokenReq” at this time asterisk see the requested protocol version as 0 and assigns the lowest protocol version which was by default 3. The phone was not able to complete the registration process for some reason, 7940 phone Reg.state struk in progress and 7961 phones say ok but the line appearance on the phone diapers and not able to make calls. If we power down and power the phone it comes back online with serverA and this time it sends a “RegisterMessage”. Looks like we are not handling the “RegisterTokenReq”. I tried setting a higher (5 and 11) number in “SCCP_DRIVER_SUPPORTED_PROTOCOL_LOW” to verify if it is related to sccp protocol verion and that did not help. I also tried giving priority 0 for both server and B in the XML file and that to did not stop the Phones registering back when the server came back online.