Cannot access device in DMZ

Trying to access the HVAC server from the outside which is on 192.168.0.50.  Tried port forwarding a port to the address but get a timeout when using internet.provider.address:port#.  Put the HVAC device address in a DMZ using the router, but still get the timeout(no :port#) and get the same.

There is a domain on the network using WSE 2016.  Any help would be grateful.

Thanks
Mike