Many airlines, QR included, fare rules have a restriction preventing customers from buying an open jaw ticket with a super long (JFK-CDG) open segment :
MILEAGE OF THE OPEN SEGMENT MUST BE EQUAL/LESS THAN
MILEAGE OF THE SHORTEST FLOWN FARE COMPONENT.
So if you don't want to buy 2 super expensive one-way JFK-DOH-COK + MAA-DOH-CDG, you might consider buying two separate tickets (and plan with a long connecting time, idealy 1 night, between your 2 separate tickets) :
1-CDG-DOH-MAA/COK-DOH-Europe
2-Europe-JFK