Just a Note....
For some reason... even though many users have apparently NOT Changed anything in confg - the entire "No Block source available" issue seems to have been going on for Multiple platforms, and Multiple types of wallets... including Master coin, Bitcoin, Litecoin, Dogecoin and others. This has been happening since at least Sep. 2013. Even though the 'addnodes' and other fixes like changing the ports
i.e. to 9150 instead of 9050 etc etc. SEEM to sometimes work. (... I personally NOW think it's coincidence that these FIXES seem to work. Since I tried one of these fixes at the same time someone else did on the east coast... theirs WORKED mine did not.)
also... I've had the same problems on Win 7 as well as PinguyOS and from Bitcoin and Masterchest and others.
Some cross platform even seem to stop at the exact same blocks. The other day numerous people in Masterchest had the "no Block Source available across the USA at least and were all behind by 27 hours....
I don't know what it is but I am still baffled. Mine suddenly started working again with NO help! and NO reinstall.
Stuck at "behind by 27 hours" and then suddenly .... all caught up! (one stuck was after completely rebuilding a 23 gig+ data base for RPCaccess... worked right up to 27 hours behind then STOPPED.