Please help with Steam multiplayer!!

Hi there:) I stuck with multiplayer. I have create game and pay STEAM. Now i release on steam and want to complite multiplayer but…
If i simulate network in engine all work fine, host-join, find games and connect to find games. I use advanced session plugin, my engine ver. 4.18
After package Steam overlay work pefectly too
But nobody see network game with Steam or with LAN. Cant direct connect by IP or STEAM id. As if there are locks in the engine for output data.
We trying it situation on different PC in different countries, but no result.
I try few time ask on but it`s like nobody knows about it problem because nobody answer.
I try find any info about possible problemm of network isolation but no info too
I try find official tutorial by UE about steam network game but it not existing

Please help in this situation, because i in deadlock now with this problem

All multiplayer it`s simple 2 node: creade advanced session and find advenced session. If any screens need just tell me