Splitting links are those links which does not redirect visitors to the proper location which they are looking for and It could happen when you have two different versions of the same web page.
The links splitting should be avoided as it should point to the Url only. It simply means that links should point to do the same URI rather than some to the index page name and others to the directory root.
Link Splitting occurs when two links have the same domain name but one starts with ‘www’ & another without ‘www’. They points to the same URI & same content. Basically, link splitting is not good for SEO.
Avoid splitting the url it will affect the ranking because google will not understand to which link to rank. so they don't rank either of the link. If there is split link we can redirect by using 301 code.
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