Experiencing a weird caching issues without any caching plugins

I figured it out. There’s a SiteGround Optimizer plugin that apparently does caching for the site. It’s bizarre. I deactivated the plugin, then reactivated it and all my changes appeared on the site when logged out. So weird.

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