Error activating watson conversation plugin

I got following error activating plugin by wp cli.
Command used is:

wp plugin install <plugin-name> –activate

default: Scaricando pacchetto di installazione da https://downloads.wp.xz.cn/plugin/conversation-watson.0.8.9.zip&#8230;
default: Scompattamento del pacchetto…
default: Installazione plugin…
default: Plugin installato correttamente.
default: Activating ‘conversation-watson’…
default: WordPress errore sul database You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘json,
default: p_status enum(“new”, “processing”) DEFAULT “new”,
default: s_created timestamp DE’ at line 4 per la query CREATE TABLE wp_watsonconv_task_runner_queue(
default: id integer(64) UNSIGNED NOT NULL AUTO_INCREMENT,
default: p_callback varchar(256) NOT NULL,
default: p_data json,
default: p_status enum(“new”, “processing”) DEFAULT “new”,
default: s_created timestamp DEFAULT CURRENT_TIMESTAMP,
default: PRIMARY KEY (id)
default: )DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci fatta da include(‘phar:///usr/local/bin/wp/php/boot-phar.php’), include(‘phar:///usr/local/bin/wp/vendor/wp-cli/wp-cli/php/wp-cli.php’), WP_CLI\bootstrap, WP_CLI\Bootstrap\LaunchRunner->process, WP_CLI\Runner->start, WP_CLI\Runner->_run_command_and_exit, WP_CLI\Runner->run_command, WP_CLI\Dispatcher\Subcommand->invoke, call_user_func, WP_CLI\Dispatcher\CommandFactory::WP_CLI\Dispatcher\{closure}, call_user_func, Plugin_Command->install, WP_CLI\CommandWithUpgrade->install, Plugin_Command->activate, activate_plugin, include_once(‘/plugins/conversation-watson/watson.php’), require_once(‘/plugins/conversation-watson/includes/background-task-runner.php’), WatsonConv\Background_Task_Runner->__construct, WatsonConv\Background_Task_Runner::check_installation, dbDelta
default: Plugin ‘conversation-watson’ activated.
default: Success: Installed 1 of 1 plugins.
default: ====== configure wordpress aspect
default: WordPress errore sul database You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘json,
default: p_status enum(“new”, “processing”) DEFAULT “new”,
default: s_created timestamp DE’ at line 4 per la query CREATE TABLE wp_watsonconv_task_runner_queue(
default: id integer(64) UNSIGNED NOT NULL AUTO_INCREMENT,
default: p_callback varchar(256) NOT NULL,
default: p_data json,
default: p_status enum(“new”, “processing”) DEFAULT “new”,
default: s_created timestamp DEFAULT CURRENT_TIMESTAMP,
default: PRIMARY KEY (id)
default: )DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci fatta da include(‘phar:///usr/local/bin/wp/php/boot-phar.php’), include(‘phar:///usr/local/bin/wp/vendor/wp-cli/wp-cli/php/wp-cli.php’), WP_CLI\bootstrap, WP_CLI\Bootstrap\LaunchRunner->process, WP_CLI\Runner->start, WP_CLI\Runner->load_wordpress, require(‘wp-settings.php’), include_once(‘/plugins/conversation-watson/watson.php’), require_once(‘/plugins/conversation-watson/includes/background-task-runner.php’), WatsonConv\Background_Task_Runner->__construct, WatsonConv\Background_Task_Runner::check_installation, dbDelta

MySqlServer version 5.5
WordPress version 5.1.1