Noise floor too low process?

The effect is detecting a part of the selection that is “totally silent”.

The most likely reasons:

  1. You have included some empty track space when applying ACX-Check (empty space will be detected as total silence, aka “-inf dB”).

  2. You used the “Silence” effect, or generated some silence into the track during editing.

  3. Some absolute silence was introduced into the track during editing by some other means.

  4. There was a “dropout” (a gap) created in the recording due to a recording problem.

The first thing to do is to try and find where the total silence(s) occur. If it’s only one place then it should be easy to fix by editing.
See this post for how to detect where the silence(s) occur: