Unable to hear caller’s voice and the caller also can't hear my voice

General Help
1

I installed recently FREEPBX 14 and everything seems to be working except for this problem:
I can’t hear caller’s voice and the caller also can’t hear my voice

2

almost always a NAT issue

3

I wish there was a better way for debugging this kind of issues
Is there a list of the screens of FREEPBX 14 where NAT option appears?

BTW, I did setup a conference and the audio is working fine there, so where should be the problem?

4

I don’t what happened. I didn’t touch anything but everything is working fine now.