Equisys Technical Notes

Technical guidance, explanations and fixes for our products



FIX: ‘Invalid Parameters’ error returned to sender when sending via Zetafax SMTP Server



ID: ZTN2109

This Zetafax technical note applies to:

  • Zetafax SMTP Server


When sending a fax from an email client using the Zetafax SMTP Server, a user receives a status reply stating that the fax was rejected, with the following text seen in the message body: ‘Status code: Internal error - Invalid parameters’


This can be caused by one or both of the following:

1.     The Zetafax SMTP Server is receiving an SMTP stream that has multiple line breaks in the FROM field. As a result, the Zetafax SMTP Server does not parse this field properly and only a partial address is forwarded onto the Zetafax Server. The truncated FROM address can be seen in the Zetafax Server Monitor as the following line: ‘Message from:’ (note that there is no data). A working system will display the following log line: ‘Message from: address@company.com’.

2.     Email addresses have not been properly populated on the Zetafax Server. The Zetafax Server expects a certain format in order to recognise a valid SMTP address. The format is as follows: ‘smtp:Display Name <address@company.com>’ (the opening and closing braces are key indicators for the SMTP parsing).</address@company.com>


  1. An update is available here to address the first issue. This includes a fix to allow Zetafax SMTP Server to parse addresses with line breaks correctly.
  2. Please refer to ZTN1418 for instructions on importing a list of SMTP users and enabling them.


This behaviour was corrected in the update and technote detailed above.

Last updated: 10th August 2016 (NT) 

Keywords: Carriage return rejected


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