[Freeswitch-dev] Failed DTMF sanity check.

Hi, I am getting "Failed DTMF sanity check" randomly (not on every call, 2 - 3 calls out of 10). Application is running using Plivo REST API, while FS receiving call from Sangoma NSG TDM gateway. I have read on FS wiki that "Failed DTMF sanity check" means FS never received RFC2833 DTMF 'end' packet. However call tcpdump shows that DTMF digits has been sent to FS from Sangoma NSG, FS showing error "Failed DTMF sanity check" and ignores the digit. Please let me know if I need to do any extra settings like editing dtmf duration or type. Best Regards, Debasish Chandra