Simple, weird problem, long research, short answer. The other evening, “something strange” happened to one of my clustered (active-active) boxes. When i arrived in the morning, the linked servers from each of the nodes to the other node was failing with the message: “Unable to complete login process due to delay in login response”. (Microsoft SQL Server, Error: 258)” Linked servers to and from all other Sql boxes were functioning. After much research, at the end of the day i had each node rebooted. Following the reboot process, the linked servers worked again. Done.