JetBlue TrueBlue - Can't book PIT to CUN without multi-city?

I am looking to book round trip PIT to CUN in May on JetBlue.com. I checked several dates and it always shows no flights are available.

However, when I select the multi-city option, it shows PIT to JFK available, departing 7:05am and arriving 8:38am. Then a JFK to CUN departing at 10:36am and another departing 12:29pm.

On the return trip, depart CUN 12:37pm and arrive JFK at 5:28pm. Depart JFK 8:00pm, arrive PIT 10:04pm.

The question is, why can't I book this round trip instead of having to make two separate multi-city bookings?

Nevermind

On the way there, the layover is 1h58m or 3h51m. On the way back, the layover is 2h32m.

I had the same problem before. Call Reservations in Salt Lake. The connection is built but there is a problem with their reservation system. The fares are currently unavailable, they can forward on the issue to JetBlue's pricing department.

Welcome to FT! That is odd; give 1-800-JETBLUE a shout. They should be able to help you out, or at least answer why this pairing is not bookable. If they can book it over the phone for you, they would probably be happy to waive the phone fee ($15) as you were unable to do so online.