Emails Sending as HTML code to recipients

I have an automated email set up that has repeatedly been just sending in coded form. A portion is here:

Errors-To: mailer@infusionmail.com
MIME-Version: 1.0
Content-Type: multipart/alternative;
boundary="----=_Part_237630_419412013.1547572591802"
X-MailSentId: 8964
X-campaignid: infusion_ac4118964
Feedback-ID: ac411:ac411_0:value:infusionsoft
X-BatchId: 0
X-InfApp: ac411
X-InfContact: 5370
X-InfSent: 50640
X-inf-package: value
X-inf-uflags: SO
X-inf-iflags: SO
X-inf-QETT: 4
X-inf-BlockName: mn34
X-inf-SRS: 18.0
X-infEng: 0
X-Inf-Campaign: 169_1824_1825
X-Inf-Src: 3
List-Unsubscribe: <https://ac411.infusionsoft.com/app/optOut/noConfirm/50640/0547ac81f38d41aa>, <mailto:unsubscribe-ac411-5370-0-50640-value@infusionmail.com>
List-Unsubscribe-Post: List-Unsubscribe=One-Click
X-CMAE-Envelope: MS4wfCRddpfhwul8r55+ddGtgq6q+nOBsiO8w5WISlmoMW8g7M4mQH5dnrmtipZhtCX+jYVfYCE+1ouY67cYl5JG1z97I0NfygiheLlwE+Pk4Z75uf5bjs2M
iOYkIIRXJTphOcFeZnqkmHRg4m1GBrZOSm8mi4O2Jw3+dl7kB+Wfr4sPsYGI1egPngF6GtTVVP1ALw==

The majority of people who respond have this type of experience. I get responses everywhere from understanding to “why would I work with you if you can’t send an email.” This has happened with several different mail servers on the receive side (gmail, yahoo, outlook, etc.) I have not been able to reproduce it sending tests to myself.
Any input/suggestions from anyone is greatly appreciated. Please Help.

Is the above what they see in the actual email? This is header information and normally, a recipient would not see this. I’ve never seen it happen before if that’s how it’s happening.

That is cut directly from their response. They called it “gobbledy gook.” The rest of the email shows the HTML code for the message like this:

<!DOCTYPE HTML PUBLIC “-//W3C//DTD XHTML 1.0 Transitional//EN” “http://www.= w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd”>
<html><head><title></title><meta name=3D"viewport" content=3D"width=3Ddevic= e-width,initial-scale=3D1.0,user-scalable=3D1" /><meta http-equiv=3D"Conten= t-Type" content=3D"text/html; charset=3Dutf-8" /><style type=3D"text/css">@= import url(http://fonts.googleapis.com/css?family=3DMerriweather:400,400italic,700=
italic,700|Open+Sans:400,400italic,700,700italic|Lato:400,400italic,700,700=

italic);</style><style type=3D"text/css">#outlook a {padding: 0;} .ReadMsgBody, .ExternalClass {width: 100%;} .ExternalClass * {line-height: 100%;} body { background-color: #ffffff; margin: 0; padding: 0;
-webkit-text-size-adjust: 100%; -ms-text-size-adjust: 100%; } table, td { border-collapse:collapse;
mso-table-lspace: 0pt; mso-table-rspace: 0pt; } img { border: 0; height: auto; line-height: 100%;

I have been testing different mail designs and trying to eliminate this. No one has been able to give me any good work around or solution.

Is this to the same email client (gmail/outlook/apple mail etc)? It looks more like a client side parsing matter.

The replies I kept where they replied and it was scrambled include: gmail.com, bellsouth.net, and lmco.com (which I would guess is powered by google.) My personal email is through gmail and my business page email is powered by them and I cannot reproduce this on a test email with anything in any campaign. Digging through all of the campaign replies I have gotten… oddly this is the only email doing this… going to do some more investigating.

If it’s the only email doing it then I definitely would delete and recreate the email and try that. Obviously if you can isolate it to that one email then ‘resetting’ would be a good step.