Website post URL not working

HI,

Yesterday i have installed W3 total cache plugin and every thing was working fine, now todays morning my site post URL is not working every post URL showing error 404 not found on this server.
i have tried to change URL type in permalink setting to by Default and its started working and then i switched to Postname its still doesnt working.

can any one has solution? because Postname% type permalink is SEO friendly and default type is not!

shall be appreciated your valued opinion