I fixed the "Netflix cannot play this title at this time" issue by upgrading Samsung Smart TV UN40EH5300 firmware to version 1033 AND deactivating Netflix and reactivating it.
To upgrade firmware i did something like below (instructions copied from earlier in thread - thank you! - and i don't think it mattered whether you had source set to TV or were in the netflix app as some mentioned above)
pressed the menu button on the remote
click to support
click to software update
took several minutes to update
download showed it updated changes 001029 through 001033
tv turned off when button pressed.
turned tv on manually
went back and logged into Netflix
logged out again it went back in automatically.
to deactivate and reactivate i followed instructions on these pages.
http://support-us.samsung.com/cyber/popup/iframe/pop_troubleshooting_fr.jsp?idx=428359&modelname=UN55F7050AF&modelcode=UN55F7050AFXZA&session_id=&from_osc=&__ncforminfo=LW6Szg3aYssFkaGPJvklgocKFz8linJpU4DCIbd5t1gEBgrFSF3UxPtlYYfp8HLg_5L5Y-OsLxHoY-9gmjsya_xhGzLnzYGXquyra2itE7H0tkGQ5AqogkEdqQLvbyG2
and
http://support-us.samsung.com/cyber/popup/iframe/pop_troubleshooting_fr.jsp?idx=425927&modelname=&modelcode=UN55F7050AFXZA&session_id=&from_osc=&__ncforminfo=PQxmAJkLfpxzlvpxC36GG5unTBEMS5iRiKotwhJSRo_3YRikq1wtdA8jWYBBrW1WgcRwMnG8vNF-oT09TmD3KJmd1LbUdUMM3OWHCs_0b1ojbRIEIhpO3cdSdErGJKbshwNb_1kPURE%3D
hope this helps - we had the issue for a while - maybe since the Apr 20 firmware upgrade? Good luck.
