drush ckeditor_media_embed:install doesn't work

Hello

3. Run drush ckeditor_media_embed:install.

It doesn't work at Drush version: 8.1.18.

$ drush8 ckeditor_media_embed:install
The drush command 'ckeditor_media_embed:install' could not be found. Run `drush cache-clear drush` to clear the commandfile cache if you have installed new extensions. [error]
Drush was not able to start (bootstrap) the Drupal database. [error]
Hint: This may occur when Drush is trying to:
* bootstrap a site that has not been installed or does not have a configured database. In this case you can select another site with a working database setup by specifying the
URI to use with the --uri parameter on the command line. See `drush topic docs-aliases` for details.
* connect the database through a socket. The socket file may be wrong or the php-cli may have no access to it in a jailed shell. See http://drupal.org/node/1428638 for details.
* connect to the database through a cli command using the --defaults-extra-file parameter to pass credentials through a tmp file. This method can break if other credentials are
specified in a ~/.my.cnf file in your home directory. You may have to delete or rename the ~/.my.cnf file in your home directory.

Drush was attempting to connect to:
Drupal version : 8.9.20
Site URI : http://default
Database driver : mysql
Database hostname : localhost
Database port : 3306
Database username : ***
Database name : ***
PHP configuration : /opt/php73/etc/php.ini
PHP OS : Linux
Drush script : /usr/bin/drush8
Drush version : 8.1.18
Drush temp directory : /tmp
Drush configuration :
Drush alias files :
Drupal root : /home/***/domains/***/web
Drupal Settings File : sites/default/settings.php
Site path : sites/default
Sync config path : ../config/sync