Hi,

This Error come when ip phone authentication is fail According to the <CiscoIPPhoneError Number="4"></CiscoIPPhoneError> Error.

so
*) if u use JTAPI then check the your network connection from your machine to CUCM machne.
*) Check the before this error your provider is created by CUCM IP, UserName & Password, if provider created successfully then check this terminal exist in this user or not.(if every thing is correct then check your network connection may be connection is break)


Over all this error will come when authentication fail.
This is My observation.



Thanks
Vinay