# Unable to download ChocoPhlAn and UniRef databases (connection error)

**URL:** <https://forum.biobakery.org/t/unable-to-download-chocophlan-and-uniref-databases-connection-error/8723>\
**Category:** HUMAnN\
**Created:** [January 21, 2026, 3:33pm UTC](https://forum.biobakery.org/t/unable-to-download-chocophlan-and-uniref-databases-connection-error/8723 "2026-01-21T15:33:14Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![sevkararda](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.biobakery.org/sevkararda/32/3540_2.png) [@sevkararda](https://forum.biobakery.org/u/sevkararda)\
**Post date:** [January 21, 2026, 3:33pm UTC](https://forum.biobakery.org/t/unable-to-download-chocophlan-and-uniref-databases-connection-error/8723/1 "2026-01-21T15:33:15Z")

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Hi everyone,

I’m trying to download the ChocoPhlAn and UniRef databases, but I keep getting connection errors.

I’m using HUMAnN v4.0.0.alpha.1.

Codes that I run:

```bash
humann_databases --download chocophlan full ./
humann_databases --download uniref uniref90_ec_filtered_diamond ./

```

Console output:

```auto

Download URL: http://huttenhower.sph.harvard.edu/humann_data/chocophlan/chocophlan.v4_alpha.tar.gz
CRITICAL ERROR: Unable to download and extract from URL: http://huttenhower.sph.harvard.edu/humann_data/chocophlan/chocophlan.v4_alpha.tar.gz

Download URL: http://huttenhower.sph.harvard.edu/humann_data/uniprot/uniref_ec_filtered/uniref90_annotated_v4_alpha_ec_filtered.tar.gz                                                     
CRITICAL ERROR: Unable to download and extract from URL: http://huttenhower.sph.harvard.edu/humann_data/uniprot/uniref_ec_filtered/uniref90_annotated_v4_alpha_ec_filtered.tar.gz                                                         

```

I also tried opening these links directly in my browser, but I get a “connection timed out” error.

Is this a server-side issue, or is there something I can do to fix this on my end?

Thanks in advance for any help.

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<div class="post-metadata">

**Author:** ![rgn5011](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.biobakery.org/rgn5011/32/3656_2.png) [@rgn5011](https://forum.biobakery.org/u/rgn5011)\
**Post date:** [March 2, 2026, 4:37pm UTC](https://forum.biobakery.org/t/unable-to-download-chocophlan-and-uniref-databases-connection-error/8723/2 "2026-03-02T16:37:46Z")

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Im having the same issue. I have been trying to download the Chocophlan and uniprot databases for the past 3 days, and I am still getting errors. I saw that @franzosa commented in the past on these database issues, do you know if there is a fix?

Thanks!

Bob

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<div class="post-metadata">

**Author:** ![sevkararda](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.biobakery.org/sevkararda/32/3540_2.png) [@sevkararda](https://forum.biobakery.org/u/sevkararda)\
**Post date:** [March 2, 2026, 4:53pm UTC](https://forum.biobakery.org/t/unable-to-download-chocophlan-and-uniref-databases-connection-error/8723/3 "2026-03-02T16:53:16Z")

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Hi there!

It looks like I ran into the server maintenance window. After waiting a few days, the issue was fixed, and I was able to download both databases without any errors.