Why can't lync clients see each other?

Question

Lync

Good afternoon.
The lync server is deployed, the clients log in - there are no problems, but they do not see each other ... I
suspect that the problem is in the SQL server - the client data is not written to the database, in turn, the clients cannot retrieve the data.
When checking the availability of the SQL database - everything goes well . There are also some problems
in the topology. I can’t imagine how to solve them, there are no transparent logs. What could be the problem and how to solve it?

Answer 1

And throw a screen of the Lync client, how is the search for a contact going? Does it search for a long time or does it crash with an error?
In theory, if everything is set by default, everything should work, maybe the firewall is blocking which of the ports.

Answer 2

the search result gives immediately here is the screen