Bing search https://www.bing.com/search?q=PR_CONNECT_RESET_ERROR
This simply means, that the peer or some middlebox in between (firewall) is terminating the connection.
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
Bing search https://www.bing.com/search?q=PR_CONNECT_RESET_ERROR
''This simply means, that the peer or some middlebox in between (firewall) is terminating the connection.''
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
[https://support.mozilla.org/en-US/kb/websites-dont-load-troubleshoot-and-fix-errors?redirectlocale=en-US&redirectslug=Error+loading+web+sites Websites don't load - troubleshoot and fix error messages]
http://kb.mozillazine.org/Error_loading_websites
[https://support.mozilla.org/en-US/kb/what-does-your-connection-is-not-secure-mean What do the security warning codes mean]