Phone not ringing with external incoming calls

[emarrufo@isutc.transcom.co.mz]

Hello guys,

I have an issue. My cisco phone CP7821 does not ring when someone tried to call from outside. Internal calls it rings and phone is working fine. I am using a the GSM Interface from PSITEK which is connected to a router. I have checked the configuration on the router and it´s pointing to that extension phone but when i tried to call using my mobile or other external line i can hear ringing but the phone (extension) does not do nothing. 

Please can you assit on this?

Edson

[Dennis Mink]

what is your cisco phone resgistered on?  cme, asterisk?

[emarrufo@isutc.transcom.co.mz]

It´s Registered in Call Manager.

[Daniele Giordano]

Is it a call manager express on a router?

Can you see the incoming call on the router?

Regards.

[emarrufo@isutc.transcom.co.mz]

No can you please assist?

[mamoussou]

Having this exact same problem. Please assist.

[shasmal18]

Hello,  I am currently having the exact same problem.  Internal calls ring fine, but Outside calls go to voicemail.