Telnet behind Linksys router

I’m trying to allow port 23 on my Linksys router to access a cisco router on my LAN.

I have enabled the local IP address with 23 in the forwarding section of the router and can also see the remote host trying to connect in the logs.

but, and here’s the thing, the remote host cannot connect to the cisco router.

If I telnet locally to the from a host on the LAN I can get in, is there something else I need to setup enable/disable.

port forwarding is working well for other services as web (port 80)

any ideas??