I have problem when I want to see stress output in CII 2017. For example, I chose Stress Summary but Allowable stress is zeros and ratio is 999%. There is no problem with input file (just a simple L shape).

How to solve?

Regards.

Not enough detail here to answer. If you're looking at B31.3 and an OPE case, this case is not a Code Compliance case, so the software sets the allowable to zero. This is just one example. Can you provide more details, or open a Support Request on Smart Support and send in the job for evaluation?