Why does the calculated Definition (D50) in my simulation report show as NaN?

D50 is defined as the ratio between the acoustic energy arriving within the first 50 ms (including the direct sound and early reflections) and the total acoustic energy of the entire impulse response at the receiver position. Therefore, it is possible that the total acoustic energy is zero or not properly computed.

I would greatly appreciate any guidance from colleagues on how to correctly calculate the Definition (D50), because as far as I understand, if D50 appears as NaN, other related acoustic parameters may also be incorrect. I have included the relevant figures (.jpeg) and model settings (.gh) below.