[bug]: SIP Alias - 'user.name' rejected because extension not found in context 'from-sip-external'

[iMiMx]

FreePBX Version

FreePBX 17

Issue Description

Running FreePBX 17, all updates installed, with guest/anon SIP calls enabled.

New extension created, 511, I can successfully call 511@freepbx.server.com - the call is routed correctly.

I then added a SIP Alias to the extension 511 for user.name - then tried calling user.name@freepbx.server.com but it results in:

NOTICE[478873] res_pjsip_session.c: anonymous: Call (UDP:xx.xx.xx.xx:31991) to extension 'user.name' rejected because extension not found in context 'from-sip-external'.

Forum post, confirmed bug by lgaetz:

https://community.freepbx.org/t/trying-to-call-sip-alias-results-in-rejected-because-extension-not-found-in-context-from-sip-external/101774/4

Operating Environment

FreePBX 17

Relevant log output

NOTICE[478873] res_pjsip_session.c: anonymous: Call (UDP:xx.xx.xx.xx:31991) to extension 'user.name' rejected because extension not found in context 'from-sip-external'.

[iMiMx]

Editing extensions.conf (/etc/asterisk), changing:

[from-sip-external]
exten => _X.,1,NoOp(Received incoming SIP connection from unknown peer to ${EXTEN})
exten => _X.,n,Set(DID=${IF($["${EXTEN:1:2}"=""]?s:${EXTEN})})
exten => _X.,n,Goto(s,1)

To:

[from-sip-external]
exten => _.,1,NoOp(Received incoming SIP connection from unknown peer to ${EXTEN})
exten => _.,n,Set(DID=${IF($["${EXTEN:1:2}"=""]?s:${EXTEN})})
exten => _.,n,Goto(s,1)

As suggested by lgaetz in the forum post, seems to resolve the issue - but obviously throws an 'altered file' warning.