Access from LAN through public IP issue

Hi there,

I have an issue how to access to my teammates SimHub dashboards. I think its not directly connected to it, but its rather a network or my WI-FI (router) related. I set the port forwarding on my router (TCP 8888 and 8889), so all the other team members CAN access to my PC and see my dashboard. But the problem is, that I CANNOT see theirs from inside of my WI-FI (behind the router).
If I login from my android telephone also from WI-FI I still cannot, only if I go from mobile network (LTE, 4G), then I CAN. So cannot access from inside my LAN to outside through their ports (btw, I can successfully ping their IP, thats not the issue). I got error Connection TimeOut.

What can cause this kind of an issue, that I cannot go through their ports to see their Simhub dashboards from my LAN WI-FI network?

Interesting is, that before I did a port forwarding, I could access to their PCs, I could see their dashboards. After port forwarding, I cannot.