Check your firewall settings
Your computer's firewall may be configured in a way that doesn't allow Chrome Remote Desktop to work properly. Verify that your firewall permits outbound UDP traffic, permits inbound UDP responses, and allows traffic on TCP ports 443 (HTTPS) and 5222 (XMPP).
Check your network’s NAT Traversal policy
If your computer is on a corporate network, check whether your company’s network security policies prevent access to outside services that rely on peer-to-peer (P2P) connections (“NAT Traversal” policies).