thanks @kernix, that tip helped me get into the admin console.
From there I could get the site back online by updating the theme & plugin
debug shows the following error:
PHP Fatal error: Cannot redeclare oceanwp_webfonts_enqueue() (previously declared in /home/vhosts/<site>/httpdocs/wordpress/wp-content/plugins/ocean-extra/includes/compatibility/ocean.php:94) in /home/vhosts/<site>/httpdocs/wordpress/wp-content/themes/oceanwp/inc/customizer/controls/typography/webfonts.php on line 128
