I have a client site that's running Simplenews with Mime Mail and SMTP Authentication Support. Everything works fine except when my client wants to include a link to a YouTube video (and just to be clear, this just a link to the video, not an attempt to embed a video in the newsletter). Here is an excerpt of the resulting newsletter email:
. . . and so on. No other links cause this to occur. When I look at the email source, the plain text version is fine. This only happens to the HTML version. I am thoroughly stumped. Has anyone seen anything like this?