Non-standart port accessing


I have an OpenWRT router running and a and a Prometheus data exporter that binds to 9100 port by default.
ref: How I monitor my OpenWrt router with Grafana Cloud and Prometheus | Grafana Labs

Here is the config
cat /etc/config/prometheus-node-exporter-lua

config prometheus-node-exporter-lua 'main'
        option listen_interface 'lan'
        option listen_ipv6 '0'
        option listen_port '9100'

I also installed tailscale on the same router and enabled it to be an exit route and provided with a subnet. I also added tailscale interface TS0 with LAN firewall settings.
ref: Tailscale on OpenWrt

Testing: Using tailscale IP I can access can access router’s GUI (port 80) but not the metrics page on port 9100. This is consistent across Windows machine in LAN, Android phone on 4g and a linux server.
While in LAN I can access the metrics data from my routers local IP.

How can I access my metrics page http://[tailscaleip]:9100/metrics on other clients?