How can I fix duplicate title tags on my WordPress website?

[sarahcuneiform22]

You can use a plugin like Yoast SEO or RankMath to set custom titles for your pages and posts, which can help prevent duplicate title tags. Install and activate the plugin on your WordPress site, then go to the settings and set custom titles for each page and post

Duplicate title tags can be caused by conflicting plugins or themes. To rule out theme problems, temporarily switch your existing WordPress theme to a new one. Go to "Appearance -> Themes" and install one of the default WordPress themes that are guaranteed not to cause a conflict. Once you've switched the theme, load your WordPress page to see if the duplicate title tags have vanished

Use a tool like Google Search Console to identify pages with duplicate title tags. Once you've identified the pages, go to the page editor and change the title tags to be unique

Copying and pasting content from other websites or sources can sometimes result in duplicate title tags. Make sure to write unique content for each page and post

[smartscraper]

Run a full audit, list URLs with duplicate titles, and modify them! 

[rahul verma]

Revisit your SEO plugins. As explained above, make sure to revisit your SEO plugins and deactivate any that aren't in use.
Deactivate Theme SEO functions. Similarly, you're going to want to deactivate any SEO functions that come with your theme.
Create a canonical URL.

[John335]

Many WordPress sites become an SEO dumpster because webmasters install 15 plugins and expect magic SERP growth. Duplicate title tags usually appear from tag pages, attachment URLs, and cloned landing pages.
Disable junk indexation, fix crawl budget leaks, and stop generating spammy archives. Rank Math handles this better than most bloated setups.