I am having the same problem on Win8 64-bit. Neither windows 8 Evernote application is working - the Metro-style one just does the loading animation forever, and the desktop app gives the "Could not connect to server" error. I installed the desktop app fresh today, but the metro-style app was installed and working earlier in the month. Evernote client on Mac works fine over same network, as does NixNote on my linux machines and Evernote iOS client. So, doesn't appear to be a network problem. I saw something somewhere that suggested it might be related to IE thinking it is offline - my IE is not in offline mode.