Only Android host fails

Hello everyone,

I made a multiplayer game using 100% BP and whenever an Android device is hosting, clients can not connect:
Host: PC, Client: PC → working
Host: PC, Client: Android → working
Host: Android, Client: PC → not working
Host: Android, Cleint: Android → not working

In project settings I added “android.permission.INTERNET” for android specific platform.

Why does it only not work when the android device is hosting? Any suggestions? Thanks in advance!