Delivery to the following recipient failed permanently

Hi everybody.

I’m using eM Client as my default mail program and I’m pretty satisfied with it. (I use it with a googlemail IMAP account.)

However, I have a problem with a single email address. Every time when I send a mail to this particular address, I get that hereinafter-called error message. It seems to be a problem with the eM Client itself because I can send Mails to this Email dress from other Mail clients or from the web. What can I do to solve this problem? Thanks for your help.
Best wishes!
Philipp

Delivery to the following recipient failed permanently:

addressee @address.com

----- Original message -----

X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
d=google.com; s=20120113;
h=x-received:from:to:subject:date:content-type:message-id
:mime-version:reply-to:user-agent:x-antivirus:x-antivirus-status;
bh=+mpZF8loMgvRl7JftncznYZ33gY6qHQZhT8FaGJuxwY=;
b=FuDMAiHT5JMsQ+TQmpy8LVbOW948dOm56a4sa9f217FG5/hUjpkg32Ka693ok4X1kf
6RVmDVg6cT16C8tck2wViHXnU7JMMr8IFmZLsbKPD23z50iCRYuXLFmc0JSlkD5+kFCH
/jkfHaQ4pBRJC2jW3NHMMxkIXm72Nn89J8CizgocoGkxk6aVszqQ12YC6iGflWm5hBbj
9GCWoYUpP7DoMyg1oHRL7bJZ/LUgDYHNwGxX4t26yLTHXotCv9AgnciLIL09Ag/RdYcQ
e4JiSJl0TzEvB51Es7S0CHF+dYOvsDDf2LhAZUMi57OI7irhx7FRcwvxaWMN5RnYqtn0
WW9Q==
X-Received: by 10.14.4.199 with SMTP id 47mr49913982eej.29.1368443128364;
Mon, 13 May 2013 04:05:28 -0700 (PDT)
Return-Path:
Received: from [127.0.0.1] (d86-33-63-119.cust.tele2.at. [86.33.63.119])
by mx.google.com with ESMTPSA id w43sm22105848eeg.14.2013.05.13.04.05.27
for
(version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128);
Mon, 13 May 2013 04:05:27 -0700 (PDT)
From: “My name”
To: addressee, addressee, addressee, addressee
Subject: Testsubjekt1234
Date: Mon, 13 May 2013 11:05:26 +0000
Content-Type: multipart/alternative;
boundary="------=_MB1FAEC7E3-F735-40BC-942E-79BAAE572F94"
Message-Id:
Mime-Version: 1.0
Reply-To: “My name”
User-Agent: eM_Client/5.0.17944.0
X-Antivirus: avast! (VPS 130513-0, 13.05.2013), Outbound message
X-Antivirus-Status: Clean
…Mailtext … …

Hi,
could you please send me the problematic message saved as .eml? Thank you very much.

wilson@emclient.com