Contents are missing but shown when switching to another theme in wordpress

This is nothing to do with plugins.

Everything on your site is using localhost. This will only work on your own machine – it will not work on a server, over the web.

You need to (at least) change the paths on your site.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)