Error 1621



Message text

Type ’%c’ not allowed before login.


Adaptive Server uses Tabular Data Stream (TDS) packets to communicate with clients. A token is attached to every TDS packet to differentiate between different types of packets. During login, Adaptive Server expects a client to supply either the TDS_LOGIN or TDS_ECHO token.

Error 1621 occurs when a client sends a token other than TDS_LOGIN or TDS_ECHO at login. Possible causes include:


To see if other processes are interfering with the port, use netstat (UNIX) or Task Manager (Windows) and check port status. You can also start the server using a different port number to remove any possible interference.

Check client applications to make sure logins are using a supported database driver. On Windows, you can use the Drivers tab under ODBC Data Source Administrator to see the available drivers.

Check the TDS login packets being sent to Adaptive Server. To identify the affected logins, you can monitor packets by using:

Correct your login scripts to remove non-printing characters or control characters, and retry the connection.

Additional information

Refer to “Starting Adaptive Server with trace flags” in the chapter “Other Useful Tasks” in the most recent version of Troubleshooting an Disaster Recovery for details on using trace flags.

Versions in which this error is raised

All versions