canonical.header-conflict
The HTTP Link header names a different canonical URL than the page's <link rel="canonical">, or names more than one.
What to change
Name one canonical URL, in one place: the <link rel="canonical"> in <head>, or the Link header (meant for PDFs and other files without HTML). Google asks not to give different canonical URLs through different methods. A CDN, plugin or platform rule often sets the header; remove the one you did not mean.
The documentation on developers.google.comA finding of this rule on a page carries the exact edits for that page: the markup it quotes, and what to write instead.
When it runs
Runs on every SEO audit: of a page, a crawl, a build directory or HTML. An error is a problem that keeps a page out of search or out of answers, or breaks how it shows there. Each finding takes 15 points off the page's score.
The severity here is the rule's usual one: a finding can be raised or lowered when the page gives a reason.
Run it, or skip it
Check a page for this rule alone, after a fix for instance:
npx @rivi-software/agentic-seo-check audit https://example.com --rule canonical.header-conflictOr from an assistant, with the MCP tool seo_audit_page:
{
"url": "https://example.com",
"rules": [
"canonical.header-conflict"
]
}To leave it out of an audit, pass --disable canonical.header-conflict on the command, or disableRules: ["canonical.header-conflict"] to a tool.
More in Canonical URLs
All 8 rules- Warning
canonical.missingNo <link rel="canonical"> is present. - Error
canonical.multipleMore than one canonical link is present. When they disagree, search engines ignore all of them. - Error
canonical.invalidThe canonical href is empty or cannot be resolved to an http(s) URL. - Warning
canonical.relativeThe canonical href is a relative URL. - Warning
canonical.protocol-mismatchThe page is served over https but the canonical points to http. - Info
canonical.other-pageThe canonical points to a different URL, so search engines will treat this page as a duplicate of that URL. - Warning
canonical.paginated-to-firstPage 2 or later of a paginated series (?page=2, /page/2/) names the first page as its canonical, so search engines may drop it and miss the items only it links to.