Rockwell 1756-L72S and AENT Module

I am using a 1756-L72S processor, in an already running line. I have a 1734-AENT module that is giving a fault code "Code 16#0010 - Mode or state of module does not allow object to perform the requested service". Google search and Rockwell suggests chassis size mismatch. Size currently matches. Looking for suggestions on how to remedy this situation. Thank you in advance for your input.

Having all the correct information is vital to troubleshooting! I was told all the LEDs were green. Updated information revealed the PointBus Status LED was flashing red! An input had failed.