Keep getting SEC_ERROR_REUSED_ISSUER_AND_SERIAL
For the last few weeks I keep getting this error message: An error occurred during a connection to ....... You are attempting to import a cert with the same issuer/serial as an existing cert, but that is not the same cert.
Error code: SEC_ERROR_REUSED_ISSUER_AND_SERIAL
It will suddenly happen for multiple sites that I have been connected to in the past, or new sites I try to open including support.mozilla.org. A solution is to clear my history and restart the browser. It only happens on my windows 10 laptop. I think happens when I have logged off or the device has slept and then firefox has restarted and opened previously open tabs. Other devices on the same network don't get effected.
Wšykne wótegrona (1)
I have this same issue against one site. I have cleared all history and cache. Cleared the certificates from the Firefox Certificate Manager. I can't get past this SEC ERROR for only one single site. And it only occurs with Firefox on one single Windows 10 box. For the site in question, Firefox on other Windows and MAC OS's work just fine.
Finally solved the problem by removing the cert9.db file from the mozilla firefox roaming profiles directory C:\Users\<user>\AppData\Roaming\Mozilla\Firefox\Profiles\51ispzkel.default-1570628920716
Wót fooshyhead