Sonarqube SAML gave error: You're not authorized to access this page. Please contact the administrator

SonarQube
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6

I came across the following link, SAML IDP Initiated Login.
And I did set the login URL like https://sonar.example.com/sessions/init/saml?return_to=%2F.
However I got an error:
The page you were looking for does not exist.