Page navi broken

wp page navi stopped appear even without plugin it show only the first page in wordpress 3.9 but it worked all the time..

ive repaired/optimized DB but its still not display the pagenavigation on wordpress… i tryed different pagenavi plugins all not work even standard wordpress back forward buttons not display … after the work on server today…
do you have an idea hat could be?

even simple this line not display:
<div class=\”navigation\”><p><?php posts_nav_link(); ?></p></div>
https://codex.ww.wp.xz.cn/Next_and_Previous_Links#The_posts_nav_link

i test this in index.php of my blog theme

“Always Show Page Navigation” if i enable this option in wp page navi it shows only one page else it shows nothing!

https://ww.wp.xz.cn/plugins/wp-pagenavi/