Max232 TX working but Rx not working
Well, 1001 reasons. Check the followings:


does the failing MAX have power? Are the capacitors properly connected for BOTH MAX (check polarity)?
can you clearly measure +8V and -8V (or more) between GND and TX output of both panels? Use a scope and send some data, if you don't have a scope then write a simple on-off-on-off application which turns the output on/off.
once you're sure that sending side ok, and you have a valid sender, go to the receiver side.
check if the receiver MAX RS232 side pin of the data line show valid voltages (there is no short or disconnect) - so the +8V, -8V what you've just made as the TX side test pattern
check if the uart side of the receiver MAX shows the same pattern with 0V, 5V. If yes, then you have a software error. If no, then you have a hardware error.