Why can't Asterisk see the peer?

Question

Asterisk

Hello!
The problem is the following, and quite funny.
I set up the Cisco 7942G phone, according to this instruction: https://habrahabr.ru/post/268821/
And, by some miracle, the following happened:
the asterisk itself does not see the registration. but from the phone, you can make outgoing calls absolutely calmly.
phone logs, in general, not a word about registration is written
asterisk debugging, in general, nothing useful is written

<--- Reliably Transmitting (no NAT) to 10.0.0.101:5160 --->
SIP/2.0 486 Busy Here
Via: SIP/2.0/UDP 10.0.0.101:5160;branch=z9hG4bK74ed2a5f;received=10.0.0.101
From: "228" <sip:[email protected]>;tag=64a0e714c52c00027155ff69-a23f7fec
To: <sip:[email protected]>;tag=as1987c369
Call-ID: [email protected]
CSeq: 102 INVITE
Server: FPBX-13.0.192.14(13.17.0)
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO, PUBLISH, MESSAGE
Supported: replaces, timer
X-Asterisk-HangupCause: Call Rejected
X-Asterisk-HangupCauseCode: 21
Content-Length: 0

<--- SIP read from UDP:10.0.0.101:49336 --->
ACK sip:[email protected] SIP/2.0
Via: SIP/2.0/UDP 10.0.0.101:5160;branch=z9hG4bK74ed2a5f
From: "228" <sip:[email protected]>;tag=64a0e714c52c00027155ff69-a23f7fec
To: <sip:[email protected]>;tag=as1987c369
Call-ID: [email protected]
Date: Tue, 18 Jul 2017 05:14:19 GMT
CSeq: 102 ACK
Content-Length: 0

Answer 1

Well, the fact that the asterisk allows you to call through itself without registration is the norm, as it should be.
And to understand why the registration does not go, see the debug during registration.