Support » Plugin: Postman SMTP Mailer/Email Log » Vanishes but I can't figure out why

  • Okay, this is weird, but here’s the concise facts:

    1) I have Postman setup with a valid email account and I send a test message to a Gmail account. Voila – right to the inbox.

    2) I try a test message to a non Gmail address, the emails never show up. So I jump out of Postman, access webmail for the account I’m using in Postman to send, and send a message to the same non-Gmail address and the emails show up. Taking Postman out of the loop removes the disappearance issue.

    This is so weird… I’ve been up all night trying to figure this out, and just can’t crack it.

    #UPDATE: I turns out all of the emails were going to SPAM on the non-Gmail account. So now I’m just trying to figure out how to keep that from happening.

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  • Another update on this – found out that CloudMark is tossing the emails due to ‘’ being in the email header. Site Ground is the web host, but if I’m using Postman to authenticate to an outside SMTP server (not hosted at Site Ground) why would the headers be polluted with this? Is there a way via Postman to make that not happen, or should I just add Site Ground to my SPF record, even though I’m not technically sending from there?

    Plugin Author Jason Hendriks


    but if I’m using Postman to authenticate to an outside SMTP server

    Are you 100% sure you are authenticating? The Session Transcript will prove useful here. Otherwise…

    There are many hosts that intercept SMTP traffic, redirecting it through their own server. It’s possible this is happening in your case. If their intent was malicious, this would be known as a man-in-the-middle attack. The Postman Connectivity Test attempts to detect this by comparing the server ID with the hostname you used, but it’s not always detectable.

    I believe this interception is only possible with no security, or STARTTLS security. SMTPS encrypts at the socket level, so if SMTPS is an option, use SMTPS security instead of STARTTLS.

    Configuring SiteGround to send your email, and yes, configuring their server in your SPF, may also solve your issue.

    Finally, using a Gmail account with the Gmail API is pretty bullet-proof.

    Hope that helps.

    Thanks Jason…. I think you’re dead on. We’re tweaking our SPF to try and get the red flags off. I hate this interception, but get why they have to do it. Your port checker utility rocks. Takes so much of the fog out of a situation.

    Plugin Author Jason Hendriks


    @theatereleven glad I could help and I hope you get it solved

Viewing 4 replies - 1 through 4 (of 4 total)
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