SMTP Error

I do get similar errors in regards to SMTP:

`Sun Oct 31 18:16:43 2021] [php7:error] [pid 8429] [client 88.74.193.155] [host teilnehmer.xxx.de] PHP Fatal error: Uncaught TypeError: Argument 1 passed to Invitation_Based_Registrations_Admin::invitation_based_registrations_configure_smtp() must be an instance of PHPMailer, instance of PHPMailer\\PHPMailer\\PHPMailer given, called in /is/htdocs/xxx/www/xxx/wp-includes/class-wp-hook.php on line 303 and defined in /is/htdocs/xxx/www/xxx/wp-content/plugins/invitation-based-registrations/admin/class-invitation-based-registrations-admin.php:90\nStack trace:\n#0 /is/htdocs/xxx/www/xxx/wp-includes/class-wp-hook.php(303): Invitation_Based_Registrations_Admin-]invitation_based_registrations_configure_smtp(Object(PHPMailer\\PHPMailer\\PHPMailer))\n#1 /is/htdocs/xxx/www/xxx/wp-includes/class-wp-hook.php(327): WP_Hook-]apply_filters(NULL, Array)\n#2 /is/htdocs/xxx/www/xxx/wp-includes/plugin.php(518): WP_Hook-]do_action(Array)\n#3 /is/htdocs/xxx/www/xxx/wp-includes/pluggable.php(538): do_a in /is/htdocs/xxx/www/xxx/wp-content/plugins/invitation-based-registrations/admin/class-invitation-based-registrations-admin.php on line 90