@Kathie, yes, Virginia, I think this is an incoming mail settings issue and not a PM issue from WikiTree. I'm going to suggest this to the WikiTreer who is having issues as I just got a pm yesterday and it does look exactly like my other mail -- no strange colors, extra small font, etc. And, I was doing exactly what you said -- checking my email settings.
I'm using MS Outlook for my mail -- I had to go to File, then way down there is an OPTIONS and under that menu -- there is accessibility. Under that -- document display options: Stationery and Fonts: There you can pick fonts, see samples, colors, etc.