I have loaded my first customized webpart into my live site. This is written in C# and performs a search on an external database, not Sharepoint one.Whenever I select the button to pass in some criteria, I see an error message"Login failed for user NT AUTHORITY\ANONYMOUS LOGON" When I look in the SQL Log files I see: "Error: 18456, Severity: 14, State: 11. Login failed for user 'NT AUTHORITY\ANONYMOUS LOGON'. Reason: Token-based server access validation failed with an infrastructure error. Check for previous errors. [CLIENT IP Address]"Have googled this message , but not found anything that relates to my problem. Enable Anonymous Access is unchecked in IIS -> Web Site -> Directory Security. Connection String has: Integrated Security=SSPI

Added a new logon to SQL Server database called NT AUTHORITY\ANONYMOUS LOGON. Made it a sysadmin and ensured it was pointing to the correct database.

And what about security? Adding NT AUTHORITY\ANONYMOUS LOGON as a LOGON and giving it SA rights is a bad thing to do.Thomas Stensitzki - MCPD, MCITP, MCTS, MCSA, MCSA:Messaging

I'm still locking the thread because the OP was satisifed with his solution and it is the OP who decides (in this case in 2010) if the thread is closed or not. I am however leaving your post as a warning. ModeratorSP 2010 "FAQ" (mainly useful links): http://wssv4faq.mindsharp.com/default.aspx WSS3/MOSS FAQ (FAQ and Links) http://wssv3faq.mindsharp.com/default.aspx Both also have links to extensive book lists and to (free) on-line chapters