New Idea 4643/Hesston 530 tailgate won't latch

Hello everyone, mew forum member here.

 

I bought a New Idea 4643 round baler this Spring and used it for the first time yesterday.  I made a few bales but also had to eject a few untied.  I eventually discovered that the tailgate isn't latching.  The tailgate closes properly against the frame but the latch mechanism doesn't move and the indicator rod doesn't go flush with the frame on top.  The manual doesn't help, I'm baffled why it won't work, all of the parts are there.  Thank you in advance.

New Idea 4643/Hesston 530 tailgate won't latch