Could you check these articles to see whether any of the potential issues identified is relevant to your system:

Which error message do you get?

• What do the security warning codes mean?
  • You can use the "Advanced" button to obtain more technical information about the problem
  • One of the more common codes users report: How to troubleshoot security error codes on secure websites

That's the message I am gettiing

Here is a copy & paste https://www.google.com.au/

Peer’s Certificate issuer is not recognized.

HTTP Strict Transport Security: false HTTP Public Key Pinning: true

Certificate chain:

MIIGvTCCBaWgAwIBAgIGDdkuBN1BMA0GCSqGSIb3DQEBCwUAMCgxEjAQBgNVBAMM CW1pdG1wcm94eTESMBAGA1UECgwJbWl0bXByb3h5MB4XDTE4MDMzMTA0MjUxM1oX DTIxMDQwMTA0MjUxM1owFzEVMBMGA1UEAwwMKi5nb29nbGUuY29tMIIBIjANBgkq hkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA15vcqa8Hb98K6uvSzMTzifs8sqBu9JCr SXxp5UDiZVdMiWUxDQLhzvoojMYkO57H1uoxafqONi0NH7+6/zJ1BrCLGrTdQ0i2 ep9KKqthu2a6NL0xiN+EuqE69QzrDATueixAk0aof/fJTf37pE5fv2Sm23EV9syc R3ip7JIsOAqOIGsLHgWS1ziwlQSOFCtAxXN3tB4pHmdgHUAU5CpvxGdbQE4ugZjh 81zNWmm1dsKSoeZxPouU/5ArIEzW4KXSfaL5hUSo6Hu477lexemJalQ6TWBYVbJe Kw65dxXsBtKB3HSgo6+l6mlBEOICjsvdhdxPJLVuPx4w0FbWSpM9oQIDAQABo4ID /DCCA/gwggP0BgNVHREEggPrMIID54IOKi5nY3AuZ3Z0Mi5jb22CCmdvb2dsZS5j b22CBiouZy5jb4IQKi51cmwuZ29vZ2xlLmNvbYIPKi5nb29nbGVhcGlzLmNuggwq Lmdvb2dsZS5jb22CBGcuY2+CDSoueW91dHViZS5jb22CFCoubWV0cmljLmdzdGF0 aWMuY29tghYqLnlvdXR1YmVlZHVjYXRpb24uY29tggsqLmdvb2dsZS5mcoISKi5n b29nbGVhZGFwaXMuY29tgg0qLmdzdGF0aWMuY29tghxkZXZlbG9wZXJzLmFuZHJv aWQuZ29vZ2xlLmNuggsqLmdvb2dsZS5ubIIKKi5ndnQxLmNvbYIPKi5nb29nbGUu Y29tLmFyggp1cmNoaW4uY29tghYqLmFwcGVuZ2luZS5nb29nbGUuY29tghhzb3Vy Y2UuYW5kcm9pZC5nb29nbGUuY26CDiouZ29vZ2xlLmNvLmpwggsqLmdvb2dsZS5o dYINKi5hbmRyb2lkLmNvbYIKd3d3Lmdvby5nbIILeW91dHViZS5jb22CCyouZ29v Z2xlLnBsghEqLmdvb2dsZXZpZGVvLmNvbYILKi5nb29nbGUuZXOCC2FuZHJvaWQu Y29tggsqLmdvb2dsZS5jbIIbZGV2ZWxvcGVyLmFuZHJvaWQuZ29vZ2xlLmNuggsq Lnl0aW1nLmNvbYIRd3d3Lmdvb2dsZS5jb20uYXWCDyouZ29vZ2xlLmNvbS5teIIK Ki5ndnQyLmNvbYIUKi5kYjgzMzk1My5nb29nbGUuY26CCyouZ29vZ2xlLmNhgg8q Lmdvb2dsZS5jb20uY2+CGmFuZHJvaWQuY2xpZW50cy5nb29nbGUuY29tghR5b3V0 dWJlZWR1Y2F0aW9uLmNvbYIOKi5nb29nbGUuY28uaW6CDyouZ29vZ2xlLmNvbS5h dYISKi5jbG91ZC5nb29nbGUuY29tgg8qLmdvb2dsZS5jb20udm6CDCouZ3N0YXRp Yy5jboIWKi55b3V0dWJlLW5vY29va2llLmNvbYIUKi5nb29nbGVjb21tZXJjZS5j b22CCHlvdXR1LmJlgg4qLmdvb2dsZS5jby51a4ILKi5nb29nbGUuZGWCFGdvb2ds ZS1hbmFseXRpY3MuY29tgg8qLmdvb2dsZS5jb20udHKCFiouZ29vZ2xlLWFuYWx5 dGljcy5jb22CDyouZ29vZ2xlLmNvbS5icoIGZ29vLmdsggcqLnl0LmJlggsqLmdv b2dsZS5wdIIFeXQuYmWCCyouZ29vZ2xlLml0ggwqLnVyY2hpbi5jb22CEmdvb2ds ZWNvbW1lcmNlLmNvbTANBgkqhkiG9w0BAQsFAAOCAQEAWYw2pRVA5xn8cdcUb/nL xneKFT2yBdqJfVBciCemCSeXmpoZadK5wBEdPvW+hf9qSVxxCbu41ytVcZY+AMwv HmYDgc9nbt5lT6f3l80D6DxHe1lVPzUncxXrT6BqpWQ/xj/jaaNPpD7yE5GxYUjE exd+/o03DkYp3qia/fJXaeHLqsUZuyJxtji7j+YZdwbA2yfk8x42/BTqzO9+Bz30 YEyoYz57MYiyty7w37ModJhISKlMR8pW8vo4KXrKBQO9wOehCwISxo+XaD8lCuiZ 0J2/RWRR4FFOe9icBclCwQaDN8fDx96srGqISnIVBvPbPDeflRb5NcmzfmD+GFez 5w==

MIIDoTCCAomgAwIBAgIGDbQpH6I6MA0GCSqGSIb3DQEBCwUAMCgxEjAQBgNVBAMM CW1pdG1wcm94eTESMBAGA1UECgwJbWl0bXByb3h5MB4XDTE3MDkyODAzNTIwMVoX DTIwMDkyOTAzNTIwMVowKDESMBAGA1UEAwwJbWl0bXByb3h5MRIwEAYDVQQKDAlt aXRtcHJveHkwggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQDXm9yprwdv 3wrq69LMxPOJ+zyyoG70kKtJfGnlQOJlV0yJZTENAuHO+iiMxiQ7nsfW6jFp+o42 LQ0fv7r/MnUGsIsatN1DSLZ6n0oqq2G7Zro0vTGI34S6oTr1DOsMBO56LECTRqh/ 98lN/fukTl+/ZKbbcRX2zJxHeKnskiw4Co4gawseBZLXOLCVBI4UK0DFc3e0Hike Z2AdQBTkKm/EZ1tATi6BmOHzXM1aabV2wpKh5nE+i5T/kCsgTNbgpdJ9ovmFRKjo e7jvuV7F6YlqVDpNYFhVsl4rDrl3FewG0oHcdKCjr6XqaUEQ4gKOy92F3E8ktW4/ HjDQVtZKkz2hAgMBAAGjgdAwgc0wDwYDVR0TAQH/BAUwAwEB/zARBglghkgBhvhC AQEEBAMCAgQweAYDVR0lBHEwbwYIKwYBBQUHAwEGCCsGAQUFBwMCBggrBgEFBQcD BAYIKwYBBQUHAwgGCisGAQQBgjcCARUGCisGAQQBgjcCARYGCisGAQQBgjcKAwEG CisGAQQBgjcKAwMGCisGAQQBgjcKAwQGCWCGSAGG+EIEATAOBgNVHQ8BAf8EBAMC AQYwHQYDVR0OBBYEFMYej0hEA6USX02yNLzM93USi0SsMA0GCSqGSIb3DQEBCwUA A4IBAQBR7LA9i453uL7HATFdw/lhcr28TQVp5nRR7RiQjpagKvb2oTHAzi3IeDj+ oWpGW3M77P/gs3t/fTfXMXSrJrXQxJolEvFWyYuPvNxNx6sqqN8xurcykJMNBVBN dEG76jLdU4QIRPsggCS4lCdM2nmtrlIwlzQAvLgTYscH2kGLN6bzRB70RNlyPCxU j2y4W7HiLzxeHyJ8RXQfnCNEl4SuhCRVO4/AXScd9VxGONpnKPn33aB8ujWpXLvg 8OZlxZQHO/ldLQzlcatr4ZVMqZRgoGa2Dq9m698iuiE9u3XFdj6Rh4HSY6JyRMHv klpnQjA/G9DxSj5R0hf/SYoKmT9R

Hmm, the issuer of the fake site certificate is listed as "mitmproxy" which is a real tool (https://mitmproxy.org/), but if you are not intentionally using it to intercept and decode your web browsing, the certificate might have been borrowed by another program with bad intentions.

Is this the first time you've gotten a certificate error on a well run site?

You might consider a malware scan: https://www.malwarebytes.com/mac/

Thanks for getting back to me It's the first time I've gotten the cert error on a well run site. I ran the malware scan - still the same issue Please help!

You can check the connection settings.

• Options/Preferences -> General -> Network: Connection -> Settings

If you do not need to use a proxy to connect to internet then try to select "No Proxy" if "Use the system proxy settings" or one of the others do not work properly.

See "Firefox connection settings":

• https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can

This worked! Thank you! But I'm not very tech savy so I don't really know what all that proxy text means.. Am i safe from malware etc by doing what you suggested?

What connection settings did you have in case you remember?

I "think" it was auto detect proxy