Problems with archives

I suppose it’s so. I can’t write post dated after 31st of August: everything after that date seems to be frozen (is successful saved but not published). But I’m able to change date even years before and archive works fine.
July archive is correct, while September reminds me to “Sorry, no posts matched your criteria” page.
I’ve tested different permalink structures (even /archives/%year%/ etc.) and, of course, .htaccess file , but outcomes are always the same.
Thank you for the answers.