metabolite identification related issue

Question

[abhisekde038]

I am doing metabolomics data analysis. This figure depicts a feature file generated through spectra processing in metaboanalyst tool. My query is why only 30% of the metabolites were annotated. I provided raw metabolomics human samples for spectra processing. Is there any easier way to annotate these unknown IDs?

I have seen different m/z values hit the same HMDB ID so annotation becomes more complex. Please tell me, is there any straightforward way?