Firefox
Deleting Outdated HPKP Key Pins in Firefox
HPKP is a great technology to pin a certificate to a website. Unless it starts blocking access to a legitimate website.
Summary
HPKP Key Pins in Firefox HPKP is a great technology to pin a certificate to a website. On first use of a domain, the browser of the client checks if key pinning is available. Upon a next visit, the browser applies an additional check if the certificate(s) provided is available in the previous list of white-listed sites. HPKP error Sometimes things go wrong with HPKP and you won’t be able to access a particular page.