If you are having trouble with indexing and crawling, there are a couple of plugins that can help. The first thing you should do is get a coverage report for your website from Google Search Console. This will give you a detailed report on the pages that could not be indexed. Then run Screaming Frog, a well-known plugin that crawls your site and gives out the best results. If you want to do it yourself, run Ahrefs SEO Audit tool and get a detailed audit of your website with other SEO tools.