Error message returned from metaphlan when running humann3


I am receiving an error message when I try to run the humann pipeline on the demo inputs provided in the biobakery tutorial.

I downloaded Metaphlan3, Humann3 and the relevant reference databases using:

conda create -n metaphlan-3.0 python=3.7
conda install metaphlan=3.0.1
pip install humann --user
humann_databases --download chocophlan full db/metaphlan_databases/
humann_databases --download uniref uniref90_diamond db/metaphlan_databases/

I ran the following command using the humann executable:

humann --input demo.fastq.gz --output demo_fastq

Then, I receive the following error message:

Error message returned from metaphlan :


Warning: Unable to download
Traceback (most recent call last):
  File "/home/noyes046/dean0358/.conda/envs/metaphlan-3.0/bin/metaphlan", line 10, in <module>
  File "/home/noyes046/dean0358/.conda/envs/metaphlan-3.0/lib/python3.7/site-packages/metaphlan/", line 916, in main
    pars['index'] = check_and_install_database(pars['index'], pars['bowtie2db'], pars['bowtie2_build'], pars['nproc'], pars['force_download'])
  File "/home/noyes046/dean0358/.conda/envs/metaphlan-3.0/lib/python3.7/site-packages/metaphlan/", line 269, in check_and_install_database
    index = resolve_latest_database(bowtie2_db, ls_f['mpa_latest'], force_redownload_latest)
UnboundLocalError: local variable 'ls_f' referenced before assignment

It looks like it is trying and failing to download one of the reference databases from Dropxbox, but I already have it installed. Is there a command-line option I can use to point humann to? Any help would be appreciated.