I am checking flange loading as per NC-3658.3 (or Peq) method on Caesar input file. However, I can't get the results giving me the message- "Output disabled for field 'Axial Force' etc "

Could someone kindly advise what the problem is?

Make sure (in the input) you have "print forces on rigids" turned on (on the Special Execution Parameters dialog), which is the default now. Also, in the Static Load Case Editor (on the Load Case Options tab), make sure you've selected a Flange Evaluation temperature for the load cases you're interested in.