I am stuck in a weird issue. I configured all of my phone numbers properly and all of them work fine. However, when I dial a DID (my own DID from one of the office numbers) from my extension, I get All Circuits Are Busy Now message. However, if I dial the same DID number from my cell phone, it works fine. This happens only to a few DID’s. Trunks and dial plans are properly configured due to which I can say I am able to dial and receive calls from all other phones. It’s only with internal extension dialing internal DID number. Also, extension to extension works fine. Any help is highly appreciated.