Issues sending UDP data from iOS device

So… i have this system sending information between different clients over udp. And it all works fine, except on iOS. I can send data to an ios device over udp and that works fine. But sending data, that doesnt seem to work. The packets doesnt seem to get sent. And it works fine from all other places.

TCP sockets from ios also works like normal. I cant really find a reason why it doesnt work…

Anyone had any experience with this?