Non English page permalink problem

Custom Structure is selected in Permalink Settings and custom permlink is setted up into “/%postname%/”.
Then post’s slug(permalink) is setted up into non English language text, so that they are working fine. But only pages are not working.
If page’s slug is setted up into English text, this is working fine.
By the way if ‘Day and name’ or ‘Month and name’ is seleced in Permlink Settings, non English pages are working fine.
I can’t know the reason.
Is it impossible to work non English pages if custom permlink is setted up into “/%postname%/”?