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TB reply with embedded base64 image gives "This is a multi-part message in MIME format....." in message body

  • 5 replies
  • 1 has this problem
  • 11 views
  • Last reply by R.Bertrand

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I am setting up an "Out of Office"-reply for my business account using rules in message filters. I have an email html signature with a logo, embedded from my sending PC (Win 10 with TB 68.3.1).

The OOO-reply goes out as expected, but I get an "This is a multi-part message in MIME format. --------------FEEB9D67C1A3FE1DEDB186F4 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 7bit" text in the message body of the replied mail while testing this between two of my mail accounts.

Exact part of the start of the mail as visible for the recipient:

This is a multi-part message in MIME format. --------------FEEB9D67C1A3FE1DEDB186F4 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 7bit Geachte....

It should just read:

Geachte....

The logo image is added at the end of the mail as base64 code, and no image is visible in my email.

Headers in the email source originating from the logo image:


FEEB9D67C1A3FE1DEDB186F4

Content-Type: image/png;

name="Mail-logo Beter Zon.png"

Content-Transfer-Encoding: base64 Content-ID: <part1.671563BA.A6D060B4@BeterZon.nl> Content-Disposition: inline;

filename="Mail-logo Beter Zon.png"

Both are unexpected at my end, but I am no expert on mail coding, just a user.

Especially the text about the multi-mime part should be interpreted as code for how to process the mail and not be shown, I think? But I also expect the image to be there as an image and not base64 code.

I know I could link to an image on a website, but I embed this image to be not dependant on images from a webserver on a location that may change over time. And secondly, most email users block external images...

Last year, I had this also on an earlier version of TB and couldn't find a solution anywhere. This time I also can't find any sources for a solution.

I am hoping someone knows what I am doing wrong and has a work around available.... Thanks in advance.

I am setting up an "Out of Office"-reply for my business account using rules in message filters. I have an email html signature with a logo, embedded from my sending PC (Win 10 with TB 68.3.1). The OOO-reply goes out as expected, but I get an "This is a multi-part message in MIME format. --------------FEEB9D67C1A3FE1DEDB186F4 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 7bit" text in the message body of the replied mail while testing this between two of my mail accounts. Exact part of the start of the mail as visible for the recipient: ******************************* This is a multi-part message in MIME format. --------------FEEB9D67C1A3FE1DEDB186F4 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 7bit Geachte.... ******************************* It should just read: ******************************* Geachte.... ******************************* The logo image is added at the end of the mail as base64 code, and no image is visible in my email. Headers in the email source originating from the logo image: ******************************** --------------FEEB9D67C1A3FE1DEDB186F4 Content-Type: image/png; name="Mail-logo Beter Zon.png" Content-Transfer-Encoding: base64 Content-ID: <part1.671563BA.A6D060B4@BeterZon.nl> Content-Disposition: inline; filename="Mail-logo Beter Zon.png" ********************************* Both are unexpected at my end, but I am no expert on mail coding, just a user. Especially the text about the multi-mime part should be interpreted as code for how to process the mail and not be shown, I think? But I also expect the image to be there as an image and not base64 code. I know I could link to an image on a website, but I embed this image to be not dependant on images from a webserver on a location that may change over time. And secondly, most email users block external images... Last year, I had this also on an earlier version of TB and couldn't find a solution anywhere. This time I also can't find any sources for a solution. I am hoping someone knows what I am doing wrong and has a work around available.... Thanks in advance.

All Replies (5)

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How did you create the signature? If it wasn't made with the HTML-format TB message composer, you can expect compatibility issues.

Apart from that, have you considered setting up the auto-reply on the mail provider's site?

https://support.mozilla.org/en-US/kb/vacation-response

Modified by sfhowes

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sfhowes said

How did you create the signature? If it wasn't made with the HTML-format TB message composer...

At first I used my own (cleanly) written html (and that works fine when sending mail myself), but after seeing the reply email I used exactly that method, making up the signature in the composer and copy-pasting it in the signature field.

During my search for a solution I also made a html file with this code (my code and the one from the composer) which I then used to point to using the second method beneath the signature field where you can set a checkmark at "use a signature file". That didn't work either.

The composer does write html differently, the image reference contains the value moz-do-not-send="false" and the source is stated as src="data:image/png;filename=Mail-logo%20Beter%20Zon.png;base64, followed with all the base64 code for the image instead of just img src="file://O:/Werk/BeterZon/Reclame/Logo/Mail-logo%20Beter%20Zon.png", but the end result is the same.

Apart from that, have you considered setting up the auto-reply on the mail provider's site?

That is indeed a possibility, but I need to get into that. This seemed to be an elegant solution in TB, whereas for the provider based solution I have to get acquainted with their way of responding and I don't even know whether I can put a logo image in their type of response...

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I did some more testing. It seems it is not so much a problem with the signature, but with the template made for the reply.

This template has the default signature at the bottom, but when I delete the image from the template, there is no code at the start of the reply.

The email source with the logo image in the template with all greater-then & less-then brackets substituted with square brackets: .... X-Antivirus-Status: Clean

This is a multi-part message in MIME format.


FEEB9D67C1A3FE1DEDB186F4

Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 7bit

[html]

 [head]
   [meta http-equiv="content-type" content="text/html; charset=UTF-8"]
 /head
 [body text="#000000" bgcolor="#FFFFFF"]
   [font face="Aller"][br]
     Geachte....

The e-mail source without the image in the template: .... X-Antivirus-Status: Clean

[html]

 [head]
   [meta http-equiv="content-type" content="text/html charset=UTF-8"]
 /head
 [body]
   Geachte....

In the latter case, I don't have the code in the message body, with an image, I have.

Apart from the image not shown in the reply while it is readily available at the start of the response, this code should not be there, am I right? So, this seems to be a bug?

I am just surprised I can't find more questions about this behaviour, so I am inclined to think that I am doing something wrong....

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I think it's probably best to start with a simple, plain text signature and see if that works properly, and then add a logo to the signature created entirely with the message composer - with no added custom html. I see a line X-Antivirus-Status: Clean, which indicates there's an antivirus program possibly adding it's own signature, e.g. "This message has been scanned by ABC antivirus", which might complicate things. Besides it not being recommended to allow AV scanning of outgoing mail, any unnecessary content injected to an auto-reply filter template should be avoided.

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Thanks for your thoughts and reaction on my issue.

The antivirus line is from my domain provider, who is doing his own AV scanning of all mail (incoming and outgoing). I can't do anything about that. There are a lot of lines from intermediate mail processes before that line. I included it to signal that that was the end of all mail processing / status lines in the source of the receiving mail and the start of the message body text.

A simple html text message template is working OK, as stated in my previous response. In fact, as things are as they are, I could make a template to be used by the OOO-rules to be send with my signature but leaving the image out - that would in effect give me the same result as I have now, with the improvement that the "multi-part message" line at the start will be missing.

However, that is no real solution to the problem as I want my logo image as part of my signature.

But maybe my setup is just so peculiar that I am the only one using TB that has this issue and it isn't a bug. Only, I really don't know where the peculiarity of my setup is located....