The value of the security.insecure_password.ui.enabled preference determines whether or not Firefox warns you about non-secure login pages. *enable the feature and be warned about non-secure login pages by setting this pref to true *disable the feature to be warned about non-secure login pages by setting this pref to false *security.insecure_password.ui.enabled = false You can disable the warning when you type in a name/password field by setting this pref to false. *security.insecure_field_warning.contextual.enabled = false There is signon.autofillForms.http for HTTP sites as an addition to the general signon.autofillForms pref to disable or enable filling a form automatically. See also: *https://support.mozilla.org/en-US/kb/insecure-password-warning-firefox *https://blog.mozilla.org/tanvi/2016/01/28/no-more-passwords-over-http-please/ *https://blog.mozilla.org/security/2017/01/20/communicating-the-dangers-of-non-secure-http/ You can open the <b>about:config</b> page via the location/address bar. You can accept the warning and click "I'll be careful" to continue. *http://kb.mozillazine.org/about:config

And please remember not to use those same HTTP site logins on any sites where you care about your identity or the data you submit.

* signon.autofillForms.http = true Works for me. I know it was mentioned in post above but it wasn't noticeable.