There is security software like Avast, Kaspersky, BitDefender and ESET that intercept secure connection certificates and send their own.

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

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

https://support.mozilla.org/en-US/kb/secure-connection-failed-error-message

https://support.mozilla.org/en-US/kb/connection-untrusted-error-message

Websites don't load - troubleshoot and fix error messages

http://kb.mozillazine.org/Error_loading_websites

What do the security warning codes mean

‘ssl_error_rx_record_too_long’ or ‘cannot display the webpage’ Internet search; More often than not, you have something misconfigured!

Try to disable IPv6 (check for other possible causes as well).

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

I have tried numerous solutions to this error code with no success. It still persists. The message is telling me to contact the site owner which I have done. I have received no response from Mozilla. Firefox is the only browser with which I am having this issue. Please advise!

What's the site address?

The site address is:

https://home.packagesear.ch/?et=20170831-ffa&g=f48631e3-0f06-4418-ab30-8b93ad5f0ec0

The error message is:

Secure Connection Failed

An error occurred during a connection to home.packagesear.ch. SSL received a record that exceeded the maximum permissible length.

Error code: SSL_ERROR_RX_RECORD_TOO_LONG

   The page you are trying to view cannot be shown because the authenticity of the received data could not be verified.
   Please contact the website owners to inform them of this problem.

Learn more…

Is there an Advanced button on this error page?

No "Advanced" button on this page

he site address is as follows:

https://home.packagesear.ch/?et=20170831-ffa&g=f48631e3-0f06-4418-ab30-8b93ad5f0ec0