Adding user and register with zoiper

I’m clearly new in freepbx and will need some clarifications and help. Currently I’m running FreePBX 13.0.42 with Asterisk 13.6.0

I’m logging into FreePBX admin panel and added new Extension, SIP Trunk.
Then I trying to Register this sip client in zoiper but is unable to register. I’ve added in Asterisk CLI sip set debug ip ip_of_the_pc where is zoiper in order to check what is happening but nothing is showed there.

Note: before to install FreePBX I was able to add user in sip.conf , extensions.conf and voicemail.conf and is registered successfully.

Enable debug completely, using “sip set debug on”.

Make sure asterisk is running and that the port (5060, or whatever you’re using) is is ‘listen’ state: “netstat -tunap | grep asterisk”.

Make sure that after you’ve created your extensions you apply the changes with the “Apply config” button on top right of the screen.

Check if iptables is not blocking your connection, try something like: “telnet HOSTIP 5060”.

Without any logs it is really hard to help.