X509: certificate signed by unknown authority


I’m trying to start docker containers with docker-compose up httpd php mysql

and I get this:

error pulling image configuration: Get https://production.cloudflare.docker.com/registry-v2/docker/registry/v2/blobs/sha256/3a/3a06fe34e4ff9471a6382901cdd5db5e565fdd6041bcb4db1a0f9ec4dc57e82e/data?verify=1553587419-oDjvfSQKoDGOMZk5O2XSCErTPOc%3D: x509: certificate signed by unknown authority

this is also not working: docker pull cytopia/bind:0.11

how to fix this?


This could probably due to many reasons. Can you try to pull any of the official Docker images:

docker pull php

If not, there might be something wrong with your Docker configuration itself. Please also state on what host operating system you are.


docker pull php is not working

Host system is Ubuntu 18.04

I’m behind proxy, proxy is configured in /etc/systemd/system/docker.service.d/http-proxy.conf


The next best way to try is to get the Proxy out of the way and try it without to see if that’s the cause.
Are you able to try this somewhere without a Proxy server in front.


No, not possible - it is corporate network.

But normally I’'m able to fetch docker images


OK, i have fixed the problem:


openssl s_client -showcerts -connect production.cloudflare.docker.com:443 < /dev/null | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' > /etc/docker/certs.d/production.cloudflare.docker.com/ca.crt

service docker restart
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