This is an error which you may get when you don't have an internet connection and you try to use a Docker functionality which needs internet access. For example:

docker search ubuntu

With no Internet connection you will get:

Error response from daemon: Get remote error: access denied

This error will appear also if you have to use a proxy server to connect to internet. In the latter case you just have to enable the proxy option in Docker. For Windows 10, click on Settings from the Docker icon in the system tray. There in the proxy tab specify the proxy settings like this:

[caption id="attachment_21" align="aligncenter" width="821"]Docker Proxy settings Docker Proxy Settings[/caption]

Make sure to click on Apply for the new settings to take effect. After that Docker will restart and you will be able to connect to internet and search:

docker search lemp
NAME                               DESCRIPTION                                     STARS     OFFICIAL   AUTOM
stenote/docker-lemp                MySQL 5.7PHP 7.0Nginx                         45                   [OK]
linuxconfig/lemp                   Automated build LEMP stack environment for...   12                   [OK]
jacobom/lemp                                                                       8                    [OK]