RTMFP (Strtatus) works stable only on a local network, not in internet

Hi,

No problem to connect two computers using RTMFP (Stratus)
on a local network.
As for connection via internet it is mostly failed.
Video streams do not start.
But sometimes connection is okay (one case for 30-60 connections).
What to do? To forget Stratus and use mediaserver?

That is to say
RTMFP connection via internet is mostly failed.
Only few times I have seen normal connection via internet.

All connections in a local network are okay.

Thanks.