The URL, which is structured as an AMP (Accelerated Mobile Pages) page, seems to be lacking the crucial <html amp> element at the top level of the document.
Why is this important?
The presence of the <html amp> element is a necessity for AMP documents. Without it, the page may not be recognized as valid AMP by search engines leading to indexing issues or absence from the search results.
What does the Optimization check?
This marker is activated whenever an AMP page is identified as being absent of the <html amp> element.
Examples that trigger this Optimization
Take the following URL as an exemplar case: https://example.com/amp-version/page1/
If this URL does not have the <html amp> or the equivalent <html ⚡> tag, the Optimization would be triggered.
How do you resolve this issue?
The solution is to insert the <html amp> tag within the <head> section (alternatively, <html ⚡> can also be used):
<!doctype html><html amp><head> <meta charset="utf-8"> <title>Your Page Title</title> ...</head>...</html>