Did you read Jim's post?
I never thought to check your resistor values because ...I thought you would have double checked that before ever asking for help.
with R14 a 1K instead of a 1M pull down...you are pulling the signal down to ground! No wonder the signal disappears at the beginning of the circuit!
R15 at 1M instead of 1K will effectively block the signal as well.
Then the signal will get sucked to ground at the end of the circuit with R15 as a 1K.
Check ALL component values and change them to the correct, listed values.