That is very strange. Are you logged into a Google account at the time you access Maps? If so, any difference in a private window where are not logged in?

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-firefox-did-not-connect https://support.mozilla.org/en-US/kb/websites-dont-load-troubleshoot-and-fix-errors [https://support.mozilla.org/en-US/kb/what-does-your-connection-is-not-secure-mean What do the security warning codes mean]

Maybe try a different DNS server. *https://support.mozilla.org/en-US/kb/firefox-dns-over-https *https://support.mozilla.org/en-US/kb/dns-over-https-doh-faqs