No soud call with system in LAN

I'm having problems with FreePBX system:
1 - when I make calls within the LAN, there is no sound during calls
2. To call on the phone from ZoIPer to ZoIPer on normal PC is connected. not vice-versa.
the system after fire. I open sip_any udp 5060.
asteisk 13, FreePBX 12
thank you.