Peer relay service running but not accepting sessions

Peer relay is configured and listening on designated ports, confirmed by 'tailscale debug peer-relay-sessions' showing Server Port and Session count fields, but session count remains at 0. Clients continue routing through DERP instead of using the peer relay.

Verify peer relay port is properly forwarded on router and accessible externally. Check that ACL includes correct tags for peer relay authorization. Confirm clients have the relay configured in their ACL. Use 'tailscale debug peer-relay-sessions' to monitor for 'no handshake' messages indicating port accessibility issues. Verify firewall rules allow inbound connections on both the standard Tailscale port and the peer relay port.