500: Unknown command, command

Severity

Recoverable error.

Explanation

An unidentifiable command is received on the server. The following list shows the valid or known commands:

• DATA
• EXPN
• HELO
• HELP
• MAIL
• NOOP
• QUEU
• QUIT
• RCPT
• RSET
• SAML
• SEND
• SOML
• TICK
• TURN
• VERB
• VRFY

The unidentifiable command is indicated at the end of the message.

System action

SMTP continues.

System programmer response

The sender issues a correct and supported SMTP command. If necessary, the user can request online help by entering HELP.

Module

SMTPCMDS

Destination

NoSuchCommand