G729 codec problem

HI

        I purchase a license for G729 codec, I installed it in my asterisk server,

every thing went fine, but now asterisk complain, here is the error message:

Unable to find a codec translation path from g729 to gsm

The first time I used gransteam IP phone, and the call very clear, then when I connect the other phones, the problem above apear,

in my asterisk server, there is a billing with gsm audio files,

is a license for g729 is only for one phone, it mean for each phone you need to have a license, and this is why I am having the problem, or some thing eles

Thank you for advance

Hello Using of G729 you can save your bandwith.But this codec is licensed one.So you should purchase it.And one more thing keep in mind that not all of the hardphones not supporting g729 codec.In grandstream gx 2000 you can see the codec on the display.which hardphone you are using.you can reach me on kgs_namboothiri@yahoo.co.in