Asterisk has no inbound incoming calls

Installed Asterisk on Synology NAS, spent hours to figure out why no incoming calls at all. Please help. Here is the situation:

  1. All Extension are in Green dot. Ext to Ext calls are OK,
  2. Out bound calls are ok.
  3. SIP providers are Registered to Flowroute and vbuzzer.
  4. Changed the extensions.conf as below, no luck
    exten=s,1,Goto(default,6000,1)
    exten=6000,1,Goto(default,6000,1)
  5. Changed the users.conf as below, no luck;
    insecure=port,invite
    fromdomain=vbuzzer.com
  6. Set a Forwarding port 5060 in the ASUS router (RT-AC68), no luck;
  7. When the Grandstream GXP1400 directly registered to SIG provider, it can make calls and receive calls, but if registered to the Asterisk PBX, it won’t receive any calls.
  8. Use X-lite on PC, same thing.

Do I miss something to change or this GUI has problem? :cry:
Please help to solve this problem.
Thank you.

Asterisk Build:
Asterisk/1.8.31.1(Was) -> (Updated to) Asterisk/13.1.0
Asterisk GUI-version : 2.1.0-rc1

Alltough this should all be solvable using Your GUI - when manual configuring extensions.conf, start reading here http://www.asteriskdocs.org/

What’s a green dot?

This board does not support GUIs and the GUI that Synology appear supplying is obsolete, so only supported by Synology.

There we have a problem :imp: :imp:
SYNOLOGY says : no support to third party packages nor forum posts follow-up in this area !

Who can help?

Asterisk GUI clearly not working with new Asterisk version 13.
Asterisk GUI not supported by SYNOLOGY.
Asterisk GUI not supported by ASTERISK.

Which GUI can be used to manage ASTERISK configurations from a Windows based PC ?

FreePBX.

FreePBX is linux based no ?
Can this safely be installed on SYNOLOGY NAS ?

I imagine only Synology could answer that.