title: SQL Server 2008 R2 Periodically Does Not Accept Connections
body: <p>I have a problem about connection pooling on Sql Server 2008 R2 environment (OS is Windows Server 2008 R2 X64). I am periodically seeing this in Sql Server error logs:</p>
  <blockquote>
  <p>Event ID:           18056</p>
  <p>Description:     The client was unable
  to reuse a session with SPID 157,
  which had been reset for connection
  pooling. The failure ID is 29. This
  error may have been caused by an
  earlier operation failing. Check the
  error logs for failed operations
  immediately before this error message.</p>
  <p>SQL 2008 and SQL 2008 R2 failure id is :   RedoLoginException,              29</p>
  </blockquote>
  <p>We have migrated to SQL Server 2008 R2 CU4, running on Windows Server 2008 R2, and the issue continues.  SQL Server is having a problem communicating with one of its domain controllers when this happens.</p>
  <p>When this happens, SQL Server Agent produces these errors:</p>
  <pre><code>[382] Logon to server 'DBINST01\DBINST01' failed (JobManager)
  [382] Logon to server 'DBINST01\DBINST01' failed (ConnUpdateJobActivity_NextScheduledRunDate) 
  [298] SQLServer Error: 258, Unable to complete login process due to delay in prelogin response [SQLSTATE 08001]
  [298] SQLServer Error: 258, TCP Provider: Timeout error [258]. [SQLSTATE 08001]
  </code></pre>
  <p>We checked the error logs for previous errors but the only error we can see is this error in the log files. What may cause this error and how can I investigate that?</p>