Call Queue not working with the Grandstream UCM6202

[ttran]

I have the T22P, T28P, T26P, T41G, T46G, and T48G and I cannot get any of them to work with call queue on the Grandstream UCM6202 IP PBX box. Calling the queue from an internal extension works fine and the phone rings, but not from the outside line. Polycom and Grandstream phones works fine. All other features work fine except the call queue.

I contacted Grandstream and they said the problem is in the Yealink phones. Any solutions?