If your plain-text or HTML emails appear truncated, get cut off abruptly, or if your CSS is acting strange, the culprit could be a period.
We've seen a few instances where some receiving email servers strip out lines that begin with periods.
We recommend that you don't begin any lines with a period in your plain-text or HTML email. Check your CSS for periods as well. You can replace any periods as the beginning of a line with a space instead.