this happened to me this afternoon too. I deleted NM from my mail client and then set it up again. During setup, I set my country and selected NM as provider. I then got a banner message sayng "setup will restart (1815)".

I repeated the setup, and although the setup dialogue suggested that I registerign a new NM account (which I of course wasn't) it still completed OK & it then synced my gmail account. The gmail account was not however visible until I stopped & restarted modest - then, all was OK again.

HTH