Hello

Troubleshoot security error codes on secure websites https://support.mozilla.org/en-US/kb/error-codes-secure-websites

If the error occurs on one site only, test it using SSL Labs https://www.ssllabs.com/ssltest

https://www.ssllabs.com/ssltest/analyze.html?d=measureadv.com, Overall Rating T, analyze at instant

Valid until Fri, 02 Jan 2026 11:28:09 UTC (expired 14 days, 20 hours ago) EXPIRED

For information purposes Customize Firefox using policies.json https://support.mozilla.org/en-US/kb/customizing-firefox-using-policiesjson

By way of illustration https://support.mozilla.org/en-US/questions/1503118

{ "policies": { "WebsiteFilter": { "Block": [ "*://*.measureadv.com/*" ] } } }

A test carried out https://www.youtube.com/watch?v=n94O49Ve1dg

Below with policies.json