I have an HTML email that I send to my users. It looks great in all major Web, Desktop, and Mobile clients even Gmail, EXCEPT when the email is included as part of a "conversation" in Gmail. In that case, some of the table background colors don't show, the text alignment is wrong, etc. Is there a way to prevent this?
Make sure your messages have different subject lines, that'll prevent them from being in a conversation. Or, if just testing, leave the subject line blank.