If you are watching on the reply from server NTP I believe you used windows w32tm service the server respond to yours ntp request with server 3 version ! If you go deeper in the sntp request when you receive the packet form the server you will make a comparation with the transmitted message and watch to see if the received header is validated in function "SNTP_valid_header" and another problem is if you watch on the flags you will have set the Unsyncronized alarm set so this means your clock source is not valid!
In the flags field you have :
b7--- b6, b5---b3, b2--b0
Alarm, NTP ver, Mode (serv/client)
So in your send packet you have 0xdc that means 11 for alarm (Unsync), 011,NTP Server ver3, and 100 mode Server
The alarm don't let you to set the correct time and give you timeout error form SNTp_oneshot !
I hope I fully clarify yours problem !