Server name cannot be determined. It must appear as the first segment of the server's dns name (servername.%1!s!). Some libraries ...

Server name cannot be determined.  It must appear as the first segment of the server's dns name (servername.%1!s!).  Some libraries do not send the server name, in which case the server name must be included as part of the user name (username@servername).  In addition, if both formats are used, the server names must match.