"policies": {
   "DNSOverHTTPS": {
     "Enabled": false,
     "Locked": true
   },
   "Preferences": {
     "network.trr.mode": {
       "Value": 5,
       "Status": "locked"
     },
     "network.dns.native_https_query": {
       "Value": false,
       "Status": "locked"
     },
     "network.trr.uri": {
       "Value": "",
       "Status": "locked"
     },
     "network.trr.bootstrapAddress": {
       "Value": "",
       "Status": "locked"
     },
     "network.trr.exclude-etc-hosts": {
       "Value": true,
       "Status": "locked"
     },
     "network.dnsCacheEntries": {
       "Value": 0,
       "Status": "locked"
     },
     "network.dns.disableIPv6": {
       "Value": true,
       "Status": "locked"
     },
     "browser.fixup.dns_first_for_single_words": {
       "Value": true,
       "Status": "locked"
     },
     "keyword.enabled": {
       "Value": false,
       "Status": "locked"
     }
   }
 }

Hi I need to block some sites through the OS Hosts file, Other browsers ( Edge, Chrome, .. ) are honoring the HOSTS file rules but Firefox bypassing them !! , I disabled the DNSOverHTTPS and all other available suggestion and options but still not honoring the hosts file ! as you can see in the attached file, the Firefox DNS Section is now blank ! but still doesn't follow the OS host file I even made a custom policy file but still doesn't work, these are the things I disabled but still not working : { "policies": { "DNSOverHTTPS": { "Enabled": false, "Locked": true }, "Preferences": { "network.trr.mode": { "Value": 5, "Status": "locked" }, "network.dns.native_https_query": { "Value": false, "Status": "locked" }, "network.trr.uri": { "Value": "", "Status": "locked" }, "network.trr.bootstrapAddress": { "Value": "", "Status": "locked" }, "network.trr.exclude-etc-hosts": { "Value": true, "Status": "locked" }, "network.dnsCacheEntries": { "Value": 0, "Status": "locked" }, "network.dns.disableIPv6": { "Value": true, "Status": "locked" }, "browser.fixup.dns_first_for_single_words": { "Value": true, "Status": "locked" }, "keyword.enabled": { "Value": false, "Status": "locked" } } } }