Fatal error on the main page after plugin activation

[mihaijoldis]

I'm on version 2.0 and just activated the plugin and on the main page I see the fatal error mesage

[20-Dec-2021 13:58:12 UTC] PHP Fatal error:  Uncaught TypeError: json_decode(): Argument #1 ($json) must be of type string, stdClass given in /Users/mishu/Desktop/Mamp-Htdocs/edd/wp-content/plugins/transients-manager/transients-manager.php:829
Stack trace:
#0 /Users/mishu/Desktop/Mamp-Htdocs/edd/wp-content/plugins/transients-manager/transients-manager.php(829): json_decode(Object(stdClass))
#1 /Users/mishu/Desktop/Mamp-Htdocs/edd/wp-content/plugins/transients-manager/transients-manager.php(795): AM_Transients_Manager->get_transient_value_type(Object(stdClass))
#2 /Users/mishu/Desktop/Mamp-Htdocs/edd/wp-content/plugins/transients-manager/transients-manager.php(320): AM_Transients_Manager->get_transient_value(Object(stdClass))
#3 /Users/mishu/Desktop/Mamp-Htdocs/edd/wp-content/plugins/transients-manager/transients-manager.php(168): AM_Transients_Manager->page_show_transients()
#4 /Users/mishu/Desktop/Mamp-Htdocs/edd/wp-includes/class-wp-hook.php(307): AM_Transients_Manager->admin('')
#5 /Users/mishu/Desktop/Mamp-Htdocs/edd/wp-includes/class-wp-hook.php(331): WP_Hook->apply_filters('', Array)
#6 /Users/mishu/Desktop/Mamp-Htdocs/edd/wp-includes/plugin.php(474): WP_Hook->do_action(Array)
#7 /Users/mishu/Desktop/Mamp-Htdocs/edd/wp-admin/admin.php(259): do_action('tools_page_tran...')
#8 /Users/mishu/Desktop/Mamp-Htdocs/edd/wp-admin/tools.php(40): require_once('/Users/mishu/De...')
#9 {main}
  thrown in /Users/mishu/Desktop/Mamp-Htdocs/edd/wp-content/plugins/transients-manager/transients-manager.php on line 829

PHP version is 8.0.8