The FTP client sent an AUTH command, REIN command, or CCC command to the server while the session was secured with TLS. The server could not complete the command because an error occurred while the server was trying to stop TLS security for the control connection.
Command: auth gssapi
>>>AUTH GSSPI
534 could not stop TLS security
The FTP server closes the connection.
Contact the system programmer.
Inspect the FTP server tracing and log messages in the SYSLOG to determine the cause of the error. If any FTP server tracing is active, the tracing that describes the error that the server encountered while stopping TLS is written to the SYSLOG. See the information about diagnosing FTP server problems with traces in z/OS Communications Server: IP Diagnosis Guide for information about FTP server tracing. The SYSLOG probably contains return code information from the gsk_secure_socket_shutdown() and gsk_secure_socket_close() calls. See the API reference information in z/OS Cryptographic Services System SSL Programming for more information about return codes from these function calls.
See the system programmer response.
z/OS® Communications Server TCP/IP: FTP