undelivered email

undelivered email

Hello,
We have some difficulties while sending an email to EuroWag.com from our email address. We can easily send/receive emails from the others, even EuroWag can send us an email but if we reply to them we receive this answer(see below) and emails are undelivered .
Thank you for the answer in the advance,
Peter

This message was created automatically by mail delivery software.

 A message that you sent could not be delivered to one or more of its recipients. This is a permanent error.

 

xxxx@eurowag.com INVALID_ADDRESS, ERROR_CODE :554, ERROR_CODE :5.7.1 Error: invalid sender by SPF from 74.201.84.163

 

 

 Received:from HP (dynamic-194-228-32-84.ipv4.broadband.iol.cz [194.228.32.84]) by mx.zohomail.com

                with SMTPS id 1460723624684261.50318029902814; Fri, 15 Apr 2016 05:33:44 -0700 (PDT)  Message-ID:<004b01d19713$04e9a990$0ebcfcb0$@xxxx.cz>

 Date:Fri, 15 Apr 2016 14:33:27 +0200

 From: <xxxxx@xxxx>  To:<xxxxx@eurowag.com>

 Subject:FW: TOLL COLLECT REGISTRATION DOCUMENTS  Content-Type:multipart/mixed;

                boundary="----=_NextPart_000_004C_01D19723.C874EA90"