Error: Artifact cannot be viewed as QIIME 2 Metadata

[jjmmii]

Hello, I'm trying to run first-distances on unweighted_unifrac_distance_matrix.qza. Here is my command:
qiime longitudinal first-distances --m-metadata-file ../metadata_with_grouping_noNC_noZymo.tsv --m-metadata-file unweighted_unifrac_distance_matrix.qza --p-state-column week --p-individual-id-column Subject --p-replicate-handling error --o-first-distances unweighted_unifrac_first_distances.qza
But returns error:

There was an issue with viewing the artifact unweighted_unifrac_distance_matrix.qza as QIIME 2 Metadata:

  Artifact <artifact: DistanceMatrix % Properties(['phylogenetic']) uuid: ae014150-2751-4060-8447-e7a7190fe789> cannot be viewed as QIIME 2 Metadata.

Thinking it may be due to old version of artifacts causing the error, I re-ran my core-metrics-phylogenetic using the latest QIIME2 version (2018.2), but the error remained. Please help look into this issue, if you need the files please PM me. Thank you very much for your help so far.

-Jamie

[jjmmii]

Another silly mistake I made, unweighted_unifrac_distance_matrix.qza should be in --i-distance-matrix not --m-metadata-file.

I'm so embarrassed that I want to delete this post but can't