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Issue Plesk operations with cURL fail

Chris Dempsey

New Pleskian
Plesk Backup Manager is configured to store backups on Amazon S3 and successfully ran daily since the server was created around 2 weeks ago.

Environment details

Plesk Obsidian v18.0.32_build20201221.13 os_Windows 2012/2016/2019
Microsoft Windows 10.0;build-14393;sp0.0;suite272;product3

On login Plesk showed error alerts

Unable to create remote backup, the local backup will be created. Error: Unable to export backup: Transport error: Extension transport: ext://s3-backup/server/: Error executing "PutObject" on "https://mybucket.s3.us-west-2.amazonaws.com/backups/plesk/system/"; AWS HTTP error: cURL error 6: Could not resolve host: mybucket.s3.us-west-2.amazonaws.com (see libcurl - Error Codes)

On viewing Backup Manager the following error alerts are shown

Warning: Could not display the list of backups in the Amazon S3 Backup storage: Unable to get dumps list: Transport error: Extension transport: ext://s3-backup/server: Error executing "ListObjects" on "https://mybucket.s3.us-west-2.amazo...s/plesk/system/&delimiter=/&encoding-type=url"; AWS HTTP error: cURL error 6: Could not resolve host: mybucket.s3.us-west-2.amazonaws.com (see libcurl - Error Codes). Please check the storage settings.

Warning: Unable to upload a file to the storage: Error executing "CreateMultipartUpload" on "https://mybucket.s3.us-west-2.amazo...test-0f818b6a1aa414175c58e2e07d42db8f?uploads"; AWS HTTP error: cURL error 6: Could not resolve host: mybucket.s3.us-west-2.amazonaws.com (see libcurl - Error Codes). Make sure you have granted the permission for multipart upload of files.

I notice the host Plesk looks for is: mybucket.s3.us-west-2.amazonaws.com however my bucket is stored in eu-west-2. I am not sure this matters though as I can connect to the bucket with the Key and Secret in FileZilla without specifying the region.

Updating the Remote Storage Settings with the same Key and Secret returns error

Error: Error executing "HeadObject" on "https://ds-skye.s3.us-west-2.amazonaws.com/backups/plesk/system/"; AWS HTTP error: cURL error 6: Could not resolve host: mybucket.s3.us-west-2.amazonaws.com (see libcurl - Error Codes)

The Plesk Dashborard Home page reports another error

Error: Failed to update the ModSecurity rule set.

To further test cURL from Plesk I updated a Let's Encrypt Certificate, this returned error

Error: Could not issue a Let's Encrypt SSL/TLS certificate for mydomain.co.uk.

Failed to connect to the Let's Encrypt server Boulder: The Let's Encrypt CA.
Please try again later or report the issue to support.
Details
Could not obtain directory: cURL error 6: Could not resolve host: acme-v02.api.letsencrypt.org (see libcurl - Error Codes)

So this looks very much like Plesk cURL is broken or misconfigured.

Next I created a simple php script to test cURL. It fails to fetch content from a text file on a remote server but successfully fetches content from a local domain (the hosts file maps the domain to the local server IP).

I tried repairing the cURL certificates with
Code:
"%plesk_cli%\repair" --update-php-curl-certificates
but this returned error

Code:
Error in cURL request: Could not resolve host: curl.haxx.se

Can anyone suggest what the cause might be or how I can investigate further?

There is a similar error linked below but this doesn't help as it's related to Plesk Linux

Thanks,

Chris
 
hello @Chris Dempsey ,

I suppose you have checked this first, but.. are you sure that your server uses DNS settings that allow to resolve remote hosts?
if you run something like
Code:
nslookup mybucket.s3.us-west-2.amazonaws.com
will it work ?
If you update your server recently it is recommended to reboot it (unfortunately in most cases reboot still useful at windows platform).

did you try to update to the latest 18.0.35.1 ?
in the 18.0.33 there was libcurl security update. so this also can be a reason.

In general I'd recommend you update your system to the latest available Obsidian and
submit request to the Plesk Technical Support for more deep investigation if this did not help.
 
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