I have logged in and just checked under "My Mumsnet" and my "Registration Details". There is a red note saying something along the lines of: that the e-mail address doesn't work and the last e-mail sent to me by MNHQ didn't work. (phrased much more professionally than that though)
I have checked the e-mail address which is fine. I haven't been getting the Round Up for several weeks. This is the only e-mail address I have used and never had problems at all, for example on the rare occasions I have reported posts or used CAT etc.
Please advise.