plugin breaks site when enabled

upon

upon enabling the plugin i get the following error which i’m only able to resolve by moving the plugin from the wp-content/plugins director

HP Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($callback) must be a valid callback, function “Artpi\WPDAOmembers_only_caps” not found or invalid function name in /var/www/html/wp-includes/class-wp-hook.php:308\nStack trace:\n#0 /var/www/html/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters()\n#1 /var/www/html/wp-includes/plugin.php(517): WP_Hook->do_action()\n#2 /var/www/html/wp-settings.php(617): do_action()\n#3 /var/www/html/wp-config.php(96): require_once(‘…’)\n#4 /var/www/html/wp-load.php(50): require_once(‘…’)\n#5 /var/www/html/wp-blog-header.php(13): require_once(‘…’)\n#6 /var/www/html/index.php(17): require(‘…’)\n#7 {main}\n thrown in /var/www/html/wp-includes/class-wp-hook.php on line 308, referer