Mails message contents not 'wrapping' (i.e. running off edge of box) I use OSX 'Mail' to look at my email.

I have received a message whose contents are not 'wrapping'.  Usually, when I resize a window the line breaks reformat so that all the message can be seen.  In this message the words run off the side of the window, even on full screen.

I am running 0S 10.14.5 on a MacBook
Looks like an HTML email has some CSS settings off the mark. Sender's fault. There is a little you can do. Hit altcmdU and see it in an even worse format but at least the text lines would break way before the width ends. 

The shortcut corresponds to View menu → Message → Raw Source.