Humann2_regroup_table for kegg : UNGROUPED!

Hi, I’m using humann2_regorup_table to convert Uniref90 into KO with mapping file “map_ko_uniref90.txt.gz” , my script is here:

humann2_regroup_table -i input_genefamily.tsv -c map_ko_uniref90.txt.gz -o output.tsv

But i found most of the reads are UNGROUPED in the output file.
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And then i found 317015 out of 352836 uniref90_ids in input_genefamily.tsv don’t have any record in the mapping file “map_ko_uniref90.txt.gz” .

I also tried to build a custom-protein-reference-database of kegg and get the KO abundance output with MinPath manually , and when i compared the new output with the former, they don’t show any consistency or statistical correlation.

Is it reasonable to get the KO abundance from the original genefamily table using humann2_regroup_table ?
Do you have any suggestion about how to get the KO abandance of a metagenome sample?

Thanks for your reply!