Inbound calls not coming

Inbound calls on certain extensions have stopped coming. Calls originating externally or internally for those extensions are getting the response “Your call can not be completed as dialed. Please check the number and dial again”.

Various test cases that I have experimented are :-

  1. Delete a problematic extension number and create a new extension number. Outcome: Same as above
  2. Create an extension in an entirely different series. Outcome: Same as above
  3. Delete a working extension and create it fresh with same extension number. Outcome: “Person at extension is unavailable. Please leave your message”.

Voip phones are having no issues as all the working-extensions are running fine on them.

For example

  1. 8083 is working fine
  2. 8084 is having no inbound call

Sip_additional settings for the above two are:-

Working fine:
[8083]
type=friend
type=friend
secret=998083
record_out=Always
record_in=Always
qualify=yes
port=5060
pickupgroup=
nat=yes
[email protected]
host=dynamic
dtmfmode=rfc2833
disallow=
dial=SIP/8083
context=from-internal
canreinvite=no
callgroup=
callerid=device <8083>
allow=
accountcode=
call-limit=50

Problematic:
[8084]
type=friend
secret=998084
record_out=Always
record_in=Always
qualify=yes
port=5060
pickupgroup=
nat=yes
[email protected]
host=dynamic
dtmfmode=rfc2833
disallow=
dial=SIP/8084
context=from-internal
canreinvite=no
callgroup=
callerid=device <8084>
allow=
accountcode=
call-limit=50

sip show peers output for the two extensions:-
Working fine:
8083/8083 121.247.129.72 D N 6460 OK (344 ms)

Problematic:
8084/8084 121.247.129.72 D N 6479 OK (343 ms)

Thanks