I'm currently using BizTalk Server 2013 R2 to exchange EDI as well as non-EDI documents using AS2 with a number of different trading partners. I recently added a new trading partner and after receiving a number of documents successfully I started seeing this error occur every now and then:

> 
> An output message of the component "Microsoft.BizTalk.EdiInt.PipelineComponents" in receive pipeline "Microsoft.BizTalk.EdiInt.DefaultPipelines.AS2Receive, Microsoft.BizTalk.Edi.EdiIntPipelines, Version=3.0.1.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" is suspended due to the following error: **The content transfer encoding quoted-printable is not supported.**.
>  The sequence number of the suspended message is 2. 
> 
> 
> 

After some investigation I found that the AS2 platform of the trading partner in question will sometimes set the `Content-Transfer-Encoding` of the MIME body part to *quoted-printable* when the enclosed XML payload contains non-ASCII characters. When this happens the message is suspended (non-resumable) with the error above.

Messages received from this trading partner are encrypted and signed, but not compressed - and received using a HTTP request-response (two-way) port configured with the out-of-the-box **AS2Receive** pipeline. I've tried using a custom pipeline with the AS Decoder, S/MIME decoder and AS2 disassembler components, but this does not seem to have any effect - the error stays the same.

I've also tried receiving unencrypted messages from the trading partner (by mutual agreement) but seem to be doing something wrong here as well as the message passed to the Message Box then ends up not being disassembled properly (the MIME part boundaries and AS2 signature is still visible in the actual message payload). Since the trading partner won't allow sending of unencrypted messages in a production environment anyway, I need to get this working with encryption. They also cannot change their platform's behavior as this will reportedly affect all of their other trading partners.

Here are the unfolded HTTP headers (ellipses denotes redacted values) of the encrypted and signed AS2 message received at the point of being suspended:

```html
Date: Mon, 20 Jan 2020 17:30:53 GMT
Content-Length: 8014
Content-Type: application/pkcs7-mime; name="smime.p7m"; smime-type=enveloped-data
From: ...
Host: ...
User-Agent: Jakarta Commons-HttpClient/3.1
AS2-To: ...
Subject: AS2 Message from ... to ...
Message-Id: <1C20200120-173053-740219@xxx.xxx.130.163>
Disposition-Notification-To: <mailto:...> ...
Disposition-Notification-Options: signed-receipt-protocol=optional, pkcs7-signature; signed-receipt-micalg=optional, sha1
AS2-From: ...
AS2-Version: 1.1
content-disposition: attachment; filename="smime.p7m"
X-Original-URL: /as2

```

Here is the unencrypted (ellipses denotes redacted content) payload when exact same message is sent from source party without encryption:

```
------=_Part_16155_1587439544.1579506174880
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

...
------=_Part_16155_1587439544.1579506174880
Content-Type: application/pkcs7-signature; name=smime.p7s; smime-type=signed-data
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="smime.p7s"
Content-Description: S/MIME Cryptographic Signature

...
------=_Part_16155_1587439544.1579506174880--

```

**Question:** does BizTalk Server support the *quoted-printable* encoding method? If it does, what am I doing wrong? If it does not, what are my options in terms of a workaround?