Update Failed: Download failed. cURL error 6: Could not resolve host:

Question

I am getting the error "Update Failed: Download failed. cURL error 6: Could not resolve host:"  on WordPress on my vps server...I have also noticed it in other applications as well.

As a consequence, WordPress network no longer allows automated install of plugins, and I think also updating them doesn't work either.

What does this usually mean? I have googled it however answers I have found seem to almost always say, check with your web host. So with that in mind i am convinced its a configuration problem that has arisen on my vps ( perhaps as a result of an update or corruption or a security setting I may have changed )

I run virtualmin control panel on top of the O/S. This forum seems to be a far better place to get answers rather than the virtualmin one.

Typically, what problem solving solutions should I try for resolving this error on a debian based system?

Answer 1

The answer is in the title of your question:

cURL error 6: Could not resolve host

The curl command failed because the system DNS could not resolve the URL provided, for whatever reason. DNS could be misconfigured on your VPS, or the URL provided could be bad/malformed/non-existent.

The problem you are encountering is one with curl and your system DNS; either curl isn't properly quering DNS (not likely, but possible), or DNS cannot resolve the URL because of misconfiguration, incorrect or non-existent URL, or related issues (highly likely).