Can't access any docker programs on a headless ubuntu from my Windows machine

docker is running on ubuntu. It works. I have a container running collabora and can access the collabora programs through owncloud.

The ubuntu system is a headless server.

To use the other docker programs that are running, I would like to log into the ubuntu server using putty and open a tunnel to the port. Then access the program in my windows browser to localhost:portnum

I know the putty tunnels work properly since I have a natively installed web console running and can access it without issue to localhost:9090 from my Windows machine.

I installed a portainer container. This is running on port 9443. If I stop the container the port closes on the ubuntu system and re-opens when I re-start the container.

When I create a putty tunnel connecting localhost to port 9443 as above, I cannot access portainer from my Windows system.

Does anyone know how to do this?