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    TroubleshootingBeginner

    Certificate Name Mismatch

    Debug certificate name mismatch errors. Understand CN vs SAN, wildcard scope, and common mistakes.

    Interactive Demo
    LinkedInX
    Name Mismatch

    What Browsers Check

    Certificate says:
    www.example.com
    vs
    Browser connecting to:
    shop.example.com
    =
    ERR_CERT_COMMON_NAME_INVALID

    Why This Matters

    Name mismatch errors prevent man-in-the-middle attacks. If an attacker presents a valid certificate for attacker.com while you're trying to reach bank.com, the browser blocks it.

    #1
    Most common SSL error
    SAN
    What browsers actually check
    Easy
    To fix once you understand it