A slow WordPress website is rarely caused by one thing. A page can be slow because the server takes too long to generate the HTML. It can be slowed down by an inefficient database query, an overloaded plugin, unoptimized images, excessive JavaScript, third-party services, poor caching, or simpl...
Source: [Dev.to](https://dev.to/toyaab/wordpress-performance-the-most-common-causes-of-slow-websites-and-how-to-diagnose-them-1hf2)