Outgoing calls work fine, but incoming calls do not ring. The Incoming call log on portal shows INVALID (C).
Tested number with Zoiper and it works fine, so its an issue with the Grandstream PBX.
I hope you are well. I see that your extension is online but when I tested the number it said the number you are trying to call is currently busy. I do not think you were on a call at the time. Please check if your DND (Do not disturb) feature is activated on the phone this feature will block all incoming calls. If you do not see a setting of that sort please send me screenshots of the features page on the web interface for the phone. I will then point out to you which feature needs to be disabled.
Phone handset does not have DND enabled.
I took a closer look at the inbound call routing and it turns out that the pattern used for analog line does not work on the SIP line. I changed the DID pattern to the following and it now works.
That's great news. Have a good weekend