Fatal Error bei Install

@ericteubert Ich nutze eine Multisite. Eben wollte ich Podlove in einer Test-Seite aktivieren und bekomme folgende Fehlermeldung im GUI ausgegeben, woran kann das liegen, ist der Server ggf. falsch konfiguriert?

Fatal error: Uncaught Error: Call to a member function add_cap() on null in /var/www/vhosts/[SERVERNAME]/wordpress/wp-content/plugins/podlove-podcasting-plugin-for-wordpress/includes/capabilities.php:25 Stack trace: #0 /var/www/vhosts/[SERVERNAME]/wordpress/wp-content/plugins/podlove-podcasting-plugin-for-wordpress/includes/capabilities.php(13): podlove_add_capability_to_roles('podlove_read_an...', Array) #1 /var/www/vhosts/[SERVERNAME]/wordpress/wp-content/plugins/podlove-podcasting-plugin-for-wordpress/plugin.php(12): podlove_init_capabilities() #2 /var/www/vhosts/[SERVERNAME]/wordpress/wp-content/plugins/podlove-podcasting-plugin-for-wordpress/plugin.php(71): Podlove\activate_for_current_blog() #3 /var/www/vhosts/[SERVERNAME]/wordpress/wp-includes/class-wp-hook.php(298): Podlove\activate('') #4 /var/www/vhosts/[SERVERNAME]/wordpress/wp-includes/class-wp-hook.php(323): WP_Hook->apply_filters('', Array) #5 /var/www/vhosts/[SERVERNAME]/wordpress/wp-includes/plugin.ph in /var/www/vhosts/[SERVERNAME]/wordpress/wp-content/plugins/podlove-podcasting-plugin-for-wordpress/includes/capabilities.php on line 25

Ist ein Ubuntu-Server und kann ggf. auch Error Logs ├╝bermitteln.