Description
When the Inbound Route’s Pattern is specified using a Direct Inbound Dialing (DID) number or the format _03x, the call fails with a prompt ‘The number you have dialed is invalid, please try again later.’ resulting in a 404 Not Found error returned by the Grandstream IP PBX UCM.
Analysis
Please enable UCM’s Syslog under PBX Module > PJSIP and set it to ALL to capture the SIP messages. The Syslog messages indicate that the INVITE request-line number is 1004, while the To header displays 0389664104. The DID Mode should be set to ‘To Header’ because 0389664100 is the destination ID.
