Instant Connection lost after joining session

Hello folks, i am having a weird issue and i am unable to find a similar issue in google.

What i want to do is a LAN game, i have my desktop as the host, it creates the session etc. Then i want the mobile devices that are connected to my WiFi to be able to find this server and join.
it works for the most part, the mobile devices do find the server, and then i hit join, it joins for a split second and then it disconnects.
I use the “Event OnNetworkError” switch to fire a print on connection lost, timeout etc. I get the connection lost one.

Using the same computer to Host, find and join the session works without a problem.

Both Server and client have the Onlinesubsystems added to their .ini. I tried both Null and Lan.
Also forwarded TCP & UDP 7777 & 6666. Disabled firewall.

I know pretty much nothing on networking so i am at my limit here, any help would be amazing. Thanks!