I have used some other email template as confirmation email html which works great, the problem im experiencing is that I cannot use the same format to send html email to the main receiver, as it is breaking the email. I probably must report it as a bug. feel free to see the original content of the html email which you can adapt or compare with your email:
<!DOCTYPE html>
<html lang="en" xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office">
<head>
<meta charset="utf-8">
<meta http-equiv="x-ua-compatible" content="ie=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta name="x-apple-disable-message-reformatting">
<title>Confirm Your Email</title>
<!--[if mso]>
<xml>
<o:OfficeDocumentSettings>
<o:AllowPNG/>
<o:PixelsPerInch>96</o:PixelsPerInch>
</o:OfficeDocumentSettings>
</xml>
<style>
table {border-collapse: collapse;}
.spacer,.divider {mso-line-height-rule:exactly;}
td,th,div,p,a {font-size: 13px; line-height: 22px;}
td,th,div,p,a,h1,h2,h3,h4,h5,h6 {font-family:"Segoe UI",Helvetica,Arial,sans-serif;}
</style>
<![endif]-->
<style type="text/css">
@import url('https://fonts.googleapis.com/css?family=Lato:300,400,700|Open+Sans');
@media only screen {
.col, td, th, div, p {font-family: "Open Sans",-apple-system,system-ui,BlinkMacSystemFont,"Segoe UI","Roboto","Helvetica Neue",Arial,sans-serif;}
.webfont {font-family: "Lato",-apple-system,system-ui,BlinkMacSystemFont,"Segoe UI","Roboto","Helvetica Neue",Arial,sans-serif;}
}
img {border: 0; line-height: 100%; vertical-align: middle;}
#outlook a, .links-inherit-color a {padding: 0; color: inherit;}
.col {font-size: 13px; line-height: 22px; vertical-align: top;}
.hover-scale:hover {transform: scale(1.2);}
.star:hover a, .star:hover ~ .star a {color: #FFCF0F!important;}
@media only screen and (max-width: 600px) {
u ~ div .wrapper {min-width: 100vw;}
.wrapper img {width: 100%!important; height: auto!important;}
.container {width: 100%!important; -webkit-text-size-adjust: 100%;}
}
@media only screen and (max-width: 480px) {
.col {
box-sizing: border-box;
display: inline-block!important;
line-height: 20px;
width: 100%!important;
}
.col-sm-1 {max-width: 25%;}
.col-sm-2 {max-width: 50%;}
.col-sm-3 {max-width: 75%;}
.col-sm-third {max-width: 33.33333%;}
.col-sm-auto {width: auto!important;}
.col-sm-push-1 {margin-left: 25%;}
.col-sm-push-2 {margin-left: 50%;}
.col-sm-push-3 {margin-left: 75%;}
.col-sm-push-third {margin-left: 33.33333%;}
.full-width-sm {display: table!important; width: 100%!important;}
.stack-sm-first {display: table-header-group!important;}
.stack-sm-last {display: table-footer-group!important;}
.stack-sm-top {display: table-caption!important; max-width: 100%; padding-left: 0!important;}
.toggle-content {
max-height: 0;
overflow: auto;
transition: max-height .4s linear;
-webkit-transition: max-height .4s linear;
}
.toggle-trigger:hover + .toggle-content,
.toggle-content:hover {max-height: 999px!important;}
.show-sm {
display: inherit!important;
font-size: inherit!important;
line-height: inherit!important;
max-height: none!important;
}
.hide-sm {display: none!important;}
.align-sm-center {
display: table!important;
float: none;
margin-left: auto!important;
margin-right: auto!important;
}
.align-sm-left {float: left;}
.align-sm-right {float: right;}
.text-sm-center {text-align: center!important;}
.text-sm-left {text-align: left!important;}
.text-sm-right {text-align: right!important;}
.nav-sm-vertical .nav-item {display: block!important;}
.nav-sm-vertical .nav-item a {display: inline-block; padding: 5px 0!important;}
.h1 {font-size: 32px !important;}
.h2 {font-size: 24px !important;}
.h3 {font-size: 16px !important;}
.borderless-sm {border: none!important;}
.height-sm-auto {height: auto!important;}
.line-height-sm-0 {line-height: 0!important;}
.overlay-sm-bg {background: #232323; background: rgba(0,0,0,0.4);}
.p-sm-0 {padding: 0!important;}
.p-sm-8 {padding: 8px!important;}
.p-sm-16 {padding: 16px!important;}
.p-sm-24 {padding: 24px!important;}
.pt-sm-0 {padding-top: 0!important;}
.pt-sm-8 {padding-top: 8px!important;}
.pt-sm-16 {padding-top: 16px!important;}
.pt-sm-24 {padding-top: 24px!important;}
.pr-sm-0 {padding-right: 0!important;}
.pr-sm-8 {padding-right: 8px!important;}
.pr-sm-16 {padding-right: 16px!important;}
.pr-sm-24 {padding-right: 24px!important;}
.pb-sm-0 {padding-bottom: 0!important;}
.pb-sm-8 {padding-bottom: 8px!important;}
.pb-sm-16 {padding-bottom: 16px!important;}
.pb-sm-24 {padding-bottom: 24px!important;}
.pl-sm-0 {padding-left: 0!important;}
.pl-sm-8 {padding-left: 8px!important;}
.pl-sm-16 {padding-left: 16px!important;}
.pl-sm-24 {padding-left: 24px!important;}
.px-sm-0 {padding-right: 0!important; padding-left: 0!important;}
.px-sm-8 {padding-right: 8px!important; padding-left: 8px!important;}
.px-sm-16 {padding-right: 16px!important; padding-left: 16px!important;}
.px-sm-24 {padding-right: 24px!important; padding-left: 24px!important;}
.py-sm-0 {padding-top: 0!important; padding-bottom: 0!important;}
.py-sm-8 {padding-top: 8px!important; padding-bottom: 8px!important;}
.py-sm-16 {padding-top: 16px!important; padding-bottom: 16px!important;}
.py-sm-24 {padding-top: 24px!important; padding-bottom: 24px!important;}
}
</style>
</head>
<body style="box-sizing:border-box;margin:0;padding:0;width:100%;word-break:break-word;-webkit-font-smoothing:antialiased;">
<div style="display:none;font-size:0;line-height:0;"><!-- Add your inbox preview text here --></div>
<table class="wrapper" cellpadding="0" cellspacing="0" role="presentation" width="100%">
<tr>
<td class="px-sm-16" align="center" bgcolor="#EEEEEE">
<table class="container" cellpadding="0" cellspacing="0" role="presentation" width="600">
<tr>
<td class="px-sm-8" align="left" bgcolor="#EEEEEE">
<div class="spacer line-height-sm-0 py-sm-8" style="line-height: 24px;">‌</div>
<table cellpadding="0" cellspacing="0" role="presentation" width="100%">
<tr>
<td class="col" align="center" width="100%">
<a href="https://example.com">
<img src="https://dummyimage.com/188x84/0CBACF/FFFFFF" alt="Header Logo" width="94">
</a>
</td>
</tr>
</table>
<div class="spacer line-height-sm-0 py-sm-8" style="line-height: 24px;">‌</div>
</td>
</tr>
</table>
</td>
</tr>
</table>
<table class="wrapper" cellpadding="0" cellspacing="0" role="presentation" width="100%">
<tr>
<td align="center" bgcolor="#EEEEEE" class="px-sm-16">
<table class="container" cellpadding="0" cellspacing="0" role="presentation" width="600">
<tr>
<td bgcolor="#0072FF" style="background: linear-gradient(to right, #00C6FF, #0072FF);">
<!--[if gte mso 9]>
<v:rect xmlns:v="urn:schemas-microsoft-com:vml" fill="true" stroke="false" style="width:600px;">
<v:fill type="gradient" color="#0072FF" color2="#00C6FF" angle="90" />
<v:textbox style="mso-fit-shape-to-text:true" inset="0,0,0,0">
<div><![endif]-->
<div class="spacer line-height-sm-0 py-sm-16" style="line-height: 32px;">‌</div>
<table cellpadding="0" cellspacing="0" role="presentation" width="100%">
<tr>
<td align="center" class="px-sm-16" style="padding: 0 96px;">
<h1 class="webfont h1" style="color: #FFFFFF; font-size: 36px; font-weight: 300; line-height: 100%; margin: 0;">Confirm your email</h1>
</td>
</tr>
</table>
<div class="spacer line-height-sm-0 py-sm-16" style="line-height: 40px;">‌</div>
<!--[if gte mso 9]></div></v:textbox></v:rect><![endif]-->
</td>
</tr>
</table>
</td>
</tr>
</table>
<table class="wrapper" cellpadding="0" cellspacing="0" role="presentation" width="100%">
<tr>
<td class="px-sm-16" align="center" bgcolor="#EEEEEE">
<table class="container" cellpadding="0" cellspacing="0" role="presentation" width="600">
<tr>
<td class="px-sm-8" align="left" bgcolor="#FFFFFF" style="padding: 0 24px;">
<div class="spacer line-height-sm-0 py-sm-8" style="line-height: 24px;">‌</div>
<table cellpadding="0" cellspacing="0" role="presentation" width="100%">
<tr>
<td class="col px-sm-16" align="center" width="100%" style="padding: 0 64px;">
<h2 style="color: #000; font-size: 20px; font-weight: 300; line-height: 28px; margin: 0 0 24px;">Hi John,</h2>
<p style="color: #888888; font-size: 16px; line-height: 24px; margin: 0;">You just created a new customer account at Sartre Store. All you have to do now is activate it:</p>
<div class="spacer" style="line-height: 32px;">‌</div>
<table cellpadding="0" cellspacing="0" role="presentation">
<tr>
<td class="webfont hover-scale" bgcolor="#0072FF" style="border-radius: 3px; transition: all 0.3s ease-in-out 0s; mso-padding-alt: 6px 32px 12px;">
<a href="https://example.com" style="color: #FFFFFF; display: inline-block; font-size: 14px; font-weight: 700; padding: 12px 32px; text-decoration: none;">Activate my account</a>
</td>
</tr>
</table>
</td>
</tr>
</table>
<div class="spacer line-height-sm-0 py-sm-8" style="line-height: 24px;">‌</div>
</td>
</tr>
</table>
</td>
</tr>
</table>
<table class="wrapper" cellpadding="0" cellspacing="0" role="presentation" width="100%">
<tr>
<td class="px-sm-16" align="center" bgcolor="#EEEEEE">
<table class="container" cellpadding="0" cellspacing="0" role="presentation" width="600">
<tr>
<td class="divider py-sm-16 px-sm-16" bgcolor="#FFFFFF" style="padding: 24px 32px;">
<div style="background: #EEEEEE; height: 1px; line-height: 1px;">‌</div>
</td>
</tr>
</table>
</td>
</tr>
</table>
<table class="wrapper" cellpadding="0" cellspacing="0" role="presentation" width="100%">
<tr>
<td class="px-sm-16" align="center" bgcolor="#EEEEEE">
<table class="container" cellpadding="0" cellspacing="0" role="presentation" width="600">
<tr>
<td class="px-sm-8" bgcolor="#FFFFFF" style="padding: 0 24px;">
<div class="spacer line-height-sm-0 py-sm-8" style="line-height: 24px;">‌</div>
<table cellpadding="0" cellspacing="0" role="presentation" width="100%">
<tr>
<td class="col" align="center" width="100%" style="padding: 0 8px;">
<div>
<img src="https://dummyimage.com/188x42" alt="Footer logo" width="94">
</div>
<div class="spacer" style="line-height: 12px;">‌</div>
<p style="color: #888888; margin: 0;">
© 2018 Sartre Email. All Rights Reserved.
</p>
<p class="links-inherit-color" style="color: #888888; margin: 0;">
126-130 Crosby Street, Soho New York City, NY 10012, U.S.
</p>
<div class="spacer line-height-sm-0 py-sm-8" style="line-height: 24px;">‌</div>
<div>
<a href="https://example.com" style="text-decoration: none;">
<img src="pinterest-light.png" alt="Pinterest" width="32">
</a>
<a href="https://example.com" style="text-decoration: none;">
<img src="twitter-light.png" alt="Twitter" width="32">
</a>
<a href="https://example.com" style="text-decoration: none;">
<img src="instagram-light.png" alt="YouTube" width="32">
</a>
</div>
<div class="spacer" style="line-height: 16px;">‌</div>
</td>
</tr>
</table>
<div class="spacer line-height-sm-0 py-sm-8" style="line-height: 24px;">‌</div>
</td>
</tr>
<tr>
<td class="px-sm-8" bgcolor="#EEEEEE" style="padding: 0 24px;">
<div class="spacer line-height-sm-0 py-sm-8" style="line-height: 24px;">‌</div>
<table cellpadding="0" cellspacing="0" role="presentation" width="100%">
<tr>
<td class="col" align="center" width="100%" style="padding: 0 8px;">
<p style="color: #888888; margin: 0;">
Questions? Reply to this email or contact us at <a href="https://example.com" style="color: #888888; text-decoration: underline;">store@sartreapp.com</a>
</p>
</td>
</tr>
</table>
<div class="spacer line-height-sm-0 py-sm-8" style="line-height: 24px;">‌</div>
</td>
</tr>
</table>
</td>
</tr>
</table>
<table class="wrapper" cellpadding="0" cellspacing="0" role="presentation" width="100%">
<tr>
<td class="px-sm-16" align="center" bgcolor="#EEEEEE">
<table class="container" cellpadding="0" cellspacing="0" role="presentation" width="600">
<tr>
<td class="spacer height-sm-auto py-sm-8" bgcolor="#EEEEEE" height="24"></td>
</tr>
</table>
</td>
</tr>
</table>
</body>
</html>