Dear Lauren,
Thanks for your reply. I believe I have identified the cause of the problem. When I tried to download the two databases onto a private laptop with sufficient storage space (as the two databases are 35 GB), the process worked using the wegt command (I have not yet tried the humann_databases command). However, when I attempted to download the databases onto our university’s Linux server (link: Accessing CREATE HPC - King's College London e-Research), none of the three commands (wget, curl, and humann_databases) worked, returning the error code ‘cannot build SSL connection’.
This is somewhat inconvenient as my university laptop does not have enough space. Consequently, I must download the databases onto another private laptop, then submit them to our server. I do not think it is an error, but it is a rather inconvenient disadvantage.
Best wishes,
Shuyuan