Can't forward a port

I spend a day searching in how to forward a port from my router to my PC, whihout success. And now I'm out of leads... and frustrated. I've seen many pages with descriptions and possible solutions but somehow I don't see the right answer. So, excusses if this is a repeating question, that is not how I see it.

This is what I try to do: I want to have access to my PC at home when I'm at work. For this I use a ddns service.

Some scenarios that work, and some that dont: This is my `standard' configuration.

I have two PC's, a desktop and a laptop. On both I have an SSH server (bitvise) and an SSH client (PuTTY) The desktop is running windows 10 and the laptop is running windows 7. I can make a SSH connection from the desktop to the laptop and the other way around, suggesting to me that port 22 is open on both computer. Right?

ISP
 |
ZyXEL VMG8324-B10A (forward port 22 to 192.168.1.105)
 | .1  (192.168.1.x)
 |
 +- .105 PC (desktop, W10, SSH server on port 22)
 |
 +- .107 PC (laptop, W7, SSH server on port 22)

The service for ddns allows me to connect to my home network. If I try to connect port 80 I just get the login screen for my router, no problems there. I even tried it with a second routeron confifured for port 8080 and the original server forwarding port 8080 to this second server. No problem.

This is what that setup does look like.

ISP
 |
ZyXEL VMG8324-B10A (forward port 8080 to 192.168.1.2)
 | .1  (192.168.1.x)
 |
 | .2
LinkSys E3000 (configuration available on port 8080)
 | .1  (10.233.1.x)

I was successfull in connecting to the configuration for LinkSys (on port 8080) via the ddns provider. No problems there. Right?

As said before, I can establish a connection between 192.168.1.105 SSH client to 192.168.1.107 SSH server and also 192.168.1.107 SSH client to 192.168.1.105 SSH server.

But I can't get a connection via ddns to any SSH server.

Now, I can see the configuration page (port 80) for ZyXEL and for LinkSys E3000 (forwarding port 8080 works). Why does it not work for port 22?

Here are the rules in ZyXEL for the forwarding:

# Status Name      WAN WAN_IP ServerIP      TriggerStart End TranslationStart End Protocol
1 active SSH       wan -      192.168.1.105 22           22   22           22   TCP/UDP
2 active http8080  wan -      192.168.1.105 8080         8080 8080         8080 TCP/UDP

Nothing strange here. And SSH communication between PC and laptop possible, nothing strange there. Where do I have to look for communication from ddns to PC? What do I forget?

Any suggestions are welcome!

Edit: 5 sept 2016.

Problem solved! With the help form the answers below I was able to iron out some configuration issues and a few minutes ago I was able to get a RDC going from my android to my PC. Nice!