We use a Cisco Web Security Appliance (proxy) to provide security for our customers. Our employees that use Firefox cannot do so after upgrading to the FireFox Quantum browser. We've tried the various strings for ntlm authentication in about:config, but none of those work. Our end users that prefer FireFox cannot use the browser until this is resolved.

network.automatic-ntlm-auth.allow-non-fqdn: true network.automatic-ntlm-auth.trusted-uris: proxy