Incompatible voice frame

I am using AMI for a product of mine. it works well normally but sometimes i found this error:

[Dec 24 16:31:56] NOTICE[7591]: channel.c:3168 __ast_read: Dropping incompatible voice frame on of format ulaw since our native format has changed to 0x100 (g729)
[Dec 24 16:31:57] NOTICE[7591]: rtp.c:1144 process_rfc3389: Comfort noise support incomplete in Asterisk (RFC 3389). Please turn off on client if possible. Client IP:

How should i solved this problem , because of this our clients are not able to hear any voice.

Help me out with this problem ,
Thank You.

Have the client turn off VAD/silence suppression.