Hi, what Security Software are you running as well your Extensions installed in Firefox as no information was provided. There is security software like Avast/AVG, Kaspersky, BitDefender, ESET & sometimes Mcafee that can prevent connections. I believe this is a little out of date but might point you in the right direction if using the above : *https://support.mozilla.org/en-US/kb/error-codes-secure-websites#w_antivirus-products If running in Private mode this is a possibility you will not get your to see your mail as you are preventing cookies. Or your settings in Options are too high for the same reasons. Please try SAFE MODE to check if Extensions or other things are the issue: *https://support.mozilla.org/kb/Safe+Mode *https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes In Firefox Safe mode these changes are effective: *all extensions are disabled (about:addons) *default theme is used (no persona) *userChrome.css and userContent.css are ignored (chrome folder) *default toolbar layout is used (file: localstore-safe.rdf) *Javascript JIT compilers are disabled (prefs: javascript.options.*jit) *hardware acceleration is disabled (Options > Advanced > General) *plugins are not affected *preferences are not affected TEST'''''''''is issue still there ?