+<p>First, try upgrading to fetchmail 6.3.18 or newer. Release 6.3.18 has
+received a considerable number of bug fixes for the authentication
+feature (AUTH, AUTHENTICATE, SASL). Most notably, fetchmail aborts SASL
+authentication attempts properly with an asterisk if it detects that it
+cannot make progress with a particular authentication scheme. This fixes
+issues where GSSAPI-enabled fetchmail cannot authenticate against
+Microsoft Exchange 2007 and 2010. <strong>Note</strong> that this is a
+bug in old fetchmail versions!</p>
+