BUG: Trouble viewing PostMark messages in HTML.

[kikosoft]

When reviewing emails in Mailwasher (v 7.12.97), that were received from https://postmarkapp.com, I noticed that they cannot be viewed in HTML. My company uses https://postmarkapp.com for all transactional emails, in HTML format, and not being able to view them is a big problem for me.

I can see the plain text version, but when I try to view the HTML version I get this message:

noHTML.png (5.21 KiB) Viewed 2464 times

This is a bug in Mailwasher, as I will explain below. Would it be possible for Firetrust to repair this bug in Mailwasher?

EXPLANATION:

The emails are shown correctly in the Outlook and Thunderbird clients on Windows 11, and I can see the HTML of emails from other sources in Mailwasher. There's something special about the way PostMark uses the multipart MIME format that trips up Mailwasher.

Below is an example of an email message. This is the raw source with the top-most receive/delivered headers removed and the email addresses changed. I took care to keep the empty lines exactly as they were.

Code: Select all

From: info@example.com
Date: Fri, 30 Dec 2022 18:36:12 +0000
Subject: Hello from Postmark!
Message-Id: <3fbdfb17-ea98-4f19-bf90-b763aad3c7fd@mtasv.net>
To: me@example.com
Feedback-ID: s9356667-_:s9356667:a142788:postmark
X-Complaints-To: abuse@example.com
X-PM-Message-Id: 3fbdfb17-ea98-4f19-bf90-b763aad3c7fd
X-PM-RCPT: |bTB8MTQyNzg4fDkzNTY2Njd8d3BkZWpvbmdAdC1tb2JpbGV0aHVpcy5ubA==|
X-PM-Message-Options: v1;9Hcc_PIAriBnYBOfaIwCcyIPcaJJ4QcTBG0Vjf0upsKfpR9qOJtFHrXwPywaBTAW0yivONdmCE8g_Gy1UcqUBBDOwW7mU_BYoMQKRhXnXR0
MIME-Version: 1.0
X-PM-MTA-Pool: transactional-3
Content-Type: multipart/alternative;
        boundary=mk3-470f5c3c4d4c47aebbab1dbc28d62e07; charset=UTF-8

--mk3-470f5c3c4d4c47aebbab1dbc28d62e07
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

This is just a friendly 'hello' from your friends at Postmark.
--mk3-470f5c3c4d4c47aebbab1dbc28d62e07
Content-Type: text/html; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

This is just a friendly <i>'hello'</i> from your friends at Postmark.
--mk3-470f5c3c4d4c47aebbab1dbc28d62e07--

I've ran some tests, and the conclusion is that the problem is the Content-Type header. This header doesn't work in Mailwasher:

Code: Select all

Content-Type: multipart/alternative;
        boundary=mk3-470f5c3c4d4c47aebbab1dbc28d62e07; charset=UTF-8

Whereas this one does:

Code: Select all

Content-Type: multipart/alternative;
        boundary=mk3-470f5c3c4d4c47aebbab1dbc28d62e07

This is clearly a bug in the way Mailwashes handles the Content-Type header, it should take note of the semi-column separator.
The source for this is RFC 2045 section 5.1:
https://www.rfc-editor.org/rfc/rfc2045#section-5.1.
The special characters are: ()<>@,;:\"/[]?=.

[TrustFire]

Not a user of https://postmarkapp.com/ . . . does the HTML render correctly if you do not throttle spam, temporarily:—

Settings >> General >> Checking Mail >> Spam Throttle >> (drag the slider all the way to the extreme right . . . towards Accuracy) 9999


ps:—
This is a mere troubleshooting exercise — not asking you to employ this . . . as your regular setting.

Personally, I'm enjoying mine on 9999 — works great for me with the all-new WebView2 Runtime.

[gingbat]

Likely fixed in the beta version... you are welcome to try this if you wish:

https://25fc482ddf92aa413bac-f38e90dc86 ... 12_110.exe

(NOTE: I advise a backup before any updates via File>>Export within MWPro just in case any unforeseen issues)

[kikosoft]

I first tested the beta version 7.12.110 and the problem persists.

I don't think this has anything to do with the spam throttle, but I can see what you mean, so I tried it. It was set to 500, and I upped it to 9999. Restarted Mailwasher and the problem is still there.

This clearly has to do with the "charset=UTF-8" after the boundary in the Content-Type header, as I explained in my initial post.

[gingbat]

I first tested the beta version 7.12.110 and the problem persists.
I don't think this has anything to do with the spam throttle, but I can see what you mean, so I tried it. It was set to 500, and I upped it to 9999. Restarted Mailwasher and the problem is still there.
This clearly has to do with the "charset=UTF-8" after the boundary in the Content-Type header, as I explained in my initial post.

OK cool, thanks for trying that anyways, we'll do some testing here and hopefully can get it sorted before too long.... .cheers!

[gingbat]

OK, we have a beta out which should fix your issue kikosoft:

https://25fc482ddf92aa413bac-f38e90dc86 ... 12_116.exe

(NOTE: I advise a backup before any updates via File>>Export within MWPro just in case any unforeseen issues)

You are welcome to try that and let me know how it all goes....

[kikosoft]

Hi Gingbat,

I'm sorry to report that this new beta hasn't solved the problem, the same error message appears when viewing the HTML version of the PostmarkApp messages.

[gingbat]

Darn, thanks for getting back to me, can you please send me the email that gives the error message....?

Send in .txt format (not inline) to 'support at firetrust dot com' refer to this post too if you could please.

To do this, open MWPro and click the "Show email info" link just above the preview pane, (Click View>>Preview Pane if you do not have this enabled) then click the "Source tab.
That will show the raw text of the email, copy that into a new txt file and send as an attachment.

Cheers!

[kikosoft]

This happens. I'm a programmer myself, so I know the process.

I've sent the full source of a PostMarkApp email to your address.

[gingbat]

Great, thanks for that email, have posted to our developer.. cheers!

[kikosoft]

This problem has now been solved by the developer in version 7.12.120 or greater.

Thank you FireTrust.