Multiple title tags issue means that website has pages with more than one title tag.
The importance of the issue
The page title is among its most crucial content elements in terms of SEO. Located in the head of an HTML document, this tag contains the header or a very concise description of the page’s content.
Bellow is a title tag sample from Sitechecker.pro:
<title>Website SEO Checker and Audit Tool: Get Your Free SEO Score</title>
Of all the content on a given page, the header is typically assigned the highest priority by search engines. In addition, it is used directly in the title bar of the browser and as the anchor text of the SERP snippet corresponding to your page.
There must be just one title tag per page so that search engines know which one to use but also to avoid diminishing its importance.
Avoid repeated or boilerplate titles. It’s important to have distinct, descriptive header for each page on your site. Titling every page on a commerce site “Cheap products for sale”, for example, makes it impossible for users to distinguish one page from another. Long headers that vary by only a single piece of information (“boilerplate” headers) are also bad; for example, a standardized header like ” – See videos, lyrics, posters, albums, reviews, and concerts” contains a lot of uninformative text. One solution is to dynamically update the title to better reflect the actual content of the page: for example, include the words “video”, “lyrics”, etc., only if that particular page contains video or lyrics. Another option is to just use “” as a concise title and use the meta description (see below) to describe your site’s content.
How to check the issue
One can identify this issue by looking at the source code. For this, just proceed to Code Viewer or use the in-built functionality of your browser. The Chrome browser allows one to check the source code by right-clicking on a neutral region of the page and selecting “View page source”.
Once the source code is available, locate the title tag by searching for text flanked by <title>.
How to fix this issue
Remove extra title tags. Leave just one.
Detect pages with multiple title tags
Crawl the website to collect all pages with more than one title tag