Semrush says sitemap.xml contains an incorrect page due to non-canonical URL

Question

I am having an issue with my home page or index.php page. When I set canonical to

<link rel="canonical" href="https://example.com/" />

I get an SEO error from Semrush for https://example.com/home saying "incorrect page found in sitemap.xml - Non-canonical URL"

If I set canonical to

<link rel="canonical" href="https://example.com/home" />

I get the SEO error for https://example.com/

With PHP I have tried the following:

<?php $currentPage = str_replace("/", "", $_SERVER['REQUEST_URI']); ?>
<link rel="canonical" href="https://example.com/<?php echo $currentPage; ?>" />

But this gives me a bunch of SEO errors saying I have duplicate title tags, duplicate content and duplicate meta description for (https://example.com/, https://example.com, https://example.com/home)

What am I doing wrong here?

Answer 1

When you have two URLs pointing to the same content, you need to mark one of them as canonical.

So if / and /home give you the same page, then both pages should say:

<link rel="canonical" href="https://example.com/">

Just to be clear: both should say that. Neither should say:

<link rel="canonical" href="https://example.com/home"><!-- this is wrong -->

In addition only the canonical page should appear in sitemap.xml. /home should not appear in sitemap.xml. (It doesn't make sense to say "Please index /home" in the sitemap only to immediately say "Don't index /home, index / instead" in the page itself)