For security reasons, I installed IP address restrictions on my FTP server on IIS 4.0. Later, I implemented a firewall and moved the IP address restriction list to the firewall. After this move, the message Source MSFTPSVC Event ID 8: FTP Server could not create a client worker Thread for user at host The connection to this user is terminated the data is the error. (No error Code) is recorded in the Event Viewer logs. Now, when users attempt to connect, they receive an error message. Why are users receiving this error message?

This error can occur in IIS 5.0 and IIS 4.0 when you add IP address restrictions in IIS, then remove them. Evidently, in some cases, the metabase is left with an invalid entry. You can use MetaEdit or Microsoft Active Directory Service Interfaces (ADSI) to remove the invalid entry. You can find details about this error in the Microsoft article "Event ID 8 When Clients Try to Access IIS FTP Site" (