What metaphlan 4.1 output shoud I use as input for humann 3.9?

Greetings, I’m a student and I’m currently trying to use humann3.9 with the metaphlan4.1 output but I’m a little bit stuck cause with both the biom and the sam the humann gives me only UNMAPPED. I know that there is also the possibility to use the humann with fastq but i need to maintain the two programs separated. The thing i wanna ask is, what is the optimal metaphlan output to give to the humann?
Thank you for your patience and have a nice week.