Search session via steam running at 50%

Hi everyone. I recently set up sessions that work through Steam, but faced such problem: I can find the session created by my friend and he can connect to me. My customers can find my session, but I can’t find it session. What could be the problem? I think I just don’t have time for the search session. How can I increase the search time? Or maybe it’s due to the fact that he closed the port?