No email header logo from development SSL server

While testing v155 during upgrade from v151 on my development system, everything seems to work except I'm not getting the header logo to appear in local email clients when operating in SSL. I either get a blue question mark, or just the alternate image text. Funny thing is that my ISP web-based email client displays the logo correctly (I'm not sure how the file is accessed from outside my firewall). The email source has both plain text and html portions. The html base href and image src point to the correct file (https://<my domain>/email/<my header image file name>). The email clients are loading remote content, either manually or automatically. I can access the image directly using a browser using the same path. The image displays correctly when operating in non-SSL mode with the email source base href and image src pointing to http://<my domain>/email/<my header image file name>. I get the same behavior in both v151 and v155.

I don't know whether the problem is Zen Cart, the development server setup, or the email client setups. Does anyone have any suggestions on further troubleshooting to isolate the problem?

Development server is MAMP PRO on MacOS 10.11.6. PHP version 6.6.30. Apple Mail and Mozilla Thunderbird are my local email clients. Zen Cart email settings are smtpauth with SMTP email account mailbox set to a gmail account which forwards all email to my ISP email account. The test customer (me) has a ZC account set to HTML email preference.

Dave

the email message arrives, so looking at smtpauth or any mail settings would IMHO be the wrong place.

from what i can tell, when looking at the email using a browser based email reader, one can see the images. the image URLs can also be seen using the same browser.

the problem is when one uses an email client (such as Apple Mail or Thunderbird) to look at the email, correct?

and if the email sources uses an image link in a non-ssl mode, it does work, true?

if so, the problem seems to me to be either the SSL certificate install, or a deep setting on your mail client. the mail client for some reason does not like your SSL certificate. i would not think the problem is ZC related.

and if the images display fine when in non-SSL mode, why not send them out that way?

good luck!

Sounds like an invalid-ssl on your dev server. Maybe expired. or self-signed. or for different domain name than what you're actually using.

I'd right-click on the image-placeholder in the received email, and choose Copy URL (or grab the URL from the email source HTML), and then paste that into a Private-Browsing Tab on a browser you don't normally use. See what it gives back as a response.

Do the same on an email where the image displays fine. Compare them. (Sounds like you've done a bit of that. But you've not shared it for anyone else to test and give feedback on.)

Thank you carlwhat for helping me sort this out. DrByte, I'm getting closer. The SSL certificate is indeed self-signed as I assumed was normal for a development system. The self-signed certificate was generated by MAMP PRO using their instructions. I was seeing the image in the web-based email client because I had set the browser I normally use to always trust the certificate for my development system domain name, the name the development system server expects. I needed to do that or I would always get an untrusted site message when accessing my zen cart store development website in SSL. When I accessed the email on my ISP website using another browser, no image was seen. But when I set that browser to always trust the certificate, the image appeared. Great! So now I have to figure out how to set my local email client up to always trust the certificate, or always trust the certificate at a system level. As a backup, I could always view the emails on the ISP web page, or back off to non-SSL as carlwhat suggests. But this has become a challenge for me to solve, even though I have other solutions. And I'm learning stuff as well.

Just to close this thread, I set the self-signed certificate to "always trust" at the system level (in Keychain Access on a Mac) and my email client can now display the email header logo in SSL mode. DrByte, thank you for the SSL certificate hint to set me on the right path.