I have multiple SSH connection strings defined in mRemoteNG and most of these hosts are accessible via a jump host. Currently, for accessing each host, I first ssh to my jump host and then to my destination host. I believe (and I had it working once on a different laptop) I should be define a proxy host in putty, leave the proxy session running. Then I in mRemoteNG, I define the putty session as proxy and directly connect to my destination. I tried the following:

1. Configured and tested a SSH2 connection to the jump host via putty. Disconnected.
2. Relaunched PuTTY, reconfigured that connection with name as proxy, hostname as jump host, and added proxy datas: Configuration -> Connection -> SSH -> Tunnels -> added source port (8100). destination (localhost:8100), selected Dynamic to see D8100 and destination (localhost8100). Attached screen-capture
3. Saved the updated session and tested PuTTY's SSH connection which worked.
4. Updated the putty session in mRemoteNG to use proxy putty session. That connection failed with "Network error: Connection timed out"

Appears I am missing a critical configuration or I configured it all wrong. Any pointers are much appreciated. Thank you for your valuable time.

Just to check, have you restarted mremote itself? I get the funny feeling it only reads putty session data when it starts but I could be wrong on that, been many patches/updates to mRemote since I last tested.

I'd also suggest testing it with normal putty sessions first, just to check the issue is or is not mremote specific.