We have a remote desktop server (2016 server) hosted in Azure. It is local domain joined and has firefox 60.0.2 installed on it. We have configured a local firefox sync server which workstations and other local remote desktop servers can connect to and use fine. We cannot seem to get the azure hosted server to connect properly and successfully sync. I have added firewall rules to allow traffic to the IPs for the below URLs. All IPs were taken from an nslookup from the server directly. accounts.firefox.com Ports 443,80 accounts-static.cdn.mozilla.net Ports 443,80 api.accounts.firefox.com Port 443 profile.accounts.firefox.com Port 443 oauth.accounts.firefox.com Port 443 updates.push.services.mozilla.com Port 443 services.addons.mozilla.org Port 443 I have the error sync log available too if required.