Firefox 52 ESR (Extended Support Release) is a landmark legacy version of the browser, primarily known for being the final release to support older operating systems like Windows XP and Windows Vista.
This is expected. Modern HTTPS standards (TLS 1.3) and certificate authorities often reject Firefox 12-51. You can try enabling older TLS versions in about:config ( security.tls.version.enable-deprecated ), but this is a security risk.
If you tell me you're using or why you need a legacy version , I can provide specific configuration tips to help you run it safely.
Actionable steps

