before i was using permalinks structure by day/name , but one day i change it to only by post,then i feel at Google search when i click at any link it shows error page not find. So i realize the problem and again change permalink form post to day/name. But know i have problem that at webmaster Google account it shows all my post have duplicate title tags issue. for example
See you didn’t find out the result as soon as changes made in permalink. Google Spider has crawl a millions of website a day. It take time to index your site. If the title tag in duplicate, then you could wait until the google reindex your site.
I am not Proficient in SEO even though i feel the same problem in 4 month before. . . Not Now 🙂