There is a user related policy restriction which is preventing the user from connecting to the target computer.
There are a number of account policies which can prevent a user from connecting to a target computer over the network. For example, by default, user accounts with empty passwords cannot access network resources.
Verify connectivity to the target computer remotely through Windows explorer or the services MMC tools. Additional information about which policy is preventing the connection may be gleaned from the event log on the target computer.