MaAsLin3 _ NA in heatmap plot

Hi ,
I have a question regarding the heatmap output. For one of the most abundant genera in my samples, the prevalence part of the heatmap shows NA.
how should I interpret this?

If the genera are very rarely absent, it’s possible that the prevalence model did not succeed in fitting because there were too few 0s. In your results file, there should be columns for N, N not zero, and error. Do these give any insight?