I use the SMTP Authentication Support module in combination with the HTML Mail module. I have set it up according to this post (https://www.drupal.org/node/1200142).
After writing the new classes as instructed in the post above, the mails are sent successfully, but all the styling is stripped in the mail.
When I use only the HTML Mail class, and don't use the SMTP class, this does not happen. But then the emails dont get through to many recipients. I need to use the SMTP Authentication to get my emails delivered.
The check box Allow to send e-mails formatted as Html
is checked in the settings for SMTP Authentication Support module.
Also, I use the htmlmail.tpl.php
template file in my theme, which works when SMTP Authentication class is not used.
Any ideas about this problem? Why is my template file ignored when using SMTP?